Indian Internet Awareness & Security

2008-09-29T10:00:00.001-07:00

When we type a web address in our browser [like www.google.com] and hit go, the request goes to our local ISP servers who translate that domain name into a hard-to-remember IP address [like 66.102.7.104]

While this address resolution mechanism is transparent to the average internet user, it can sometimes be the main reason for slow internet access if the DNS servers of your ISP are acting choppy or not working at all.

To overcome these problems, you can consider changing your DNS server name to a more reliable but free service called OpenDNS. There's no software to install, just a small tweak in your internet connection settings.

We just replaced the default DSN server address of our ISP with the OpenDNS servers which are :

208.67.222.222
208.67.220.220

The DNS server can be changed from the TCP/IP Properties section. [Control Panel -> Network Connections -> Local Network Connection -> TCP IP Properties]

Why OpenDNS is good ? Your domain resolution request to OpenDNS is executed from the nearest physical location and the address are also cached at their end. Therefore you notice faster internet browsing.

Second OpenDNS would auto-correct misspelled domain names [or typos]. For instance, if you type www.gooogle.com by mistake, you'll be redirected to www.google.com without any interventation. The other advantage is that you have a much safer browsing experience since OpenDNS would prevent you from visiting a scam website by error.

Some precautions before using OpenDNS

1. In the extreme situation when OpenDNS servers go down, you should keep the address of your ISP DNS servers handy.

2. You can turn off the phishing protection or auto typo correction by visiting the OpenDNS preferences page.

3. Some users might have privacy concerns with OpenDNS while some dislike seeing ads when they mis-spell domain names. The choice is completely your's here.

XP: Speed Up Network Browsing

2008-09-29T09:59:00.001-07:00

XP: Speed Up Network Browsing

Who knows why, but XP first checks for scheduled tasks on a target machine before it will list the files and folders for that target machine.

We've all seen this. You click on a network computer to browse... and you sit there and wait. We can download files screaming quick, but, man, that first delay is a killer.

Somebody will probably leave a comment that this delay is needed to prevent the world from coming to an end. That 15 to 30 seconds drives me crazy... and this is how to stop it.

This involves the registry so backup your registry before trying this. Heck, you probably should back up your whole computer and take out life insurance as well.

In regedit navigate to:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\
Explorer\Remote Computer\NameSpace

And delete the following key:
{D6277990-4C6A-11CF-8D87-00AA0060F5BF}

Close regedit and reboot.

This should turn off the check for scheduled tasks before browsing... and get rid of that blasted delay.

PREVENTING HACKS THROUGH NULL SESSIONS

2008-09-29T09:58:00.000-07:00

PREVENTING HACKS THROUGH NULL SESSIONS

All variations of the Windows NT kernel have a major security flaw: They allow a peculiar form of access called a null or anonymous session, which can yield dangerous information about a machine and its SAM (Security Accounts Manager) accounts. SAM is a local security database that stores information about all of a machine's user and group accounts. Discovering a SAM account with administrative privileges would be a hacker's first objective—but getting the name of any account is a big step. With a user name, a hacker has a hope of eventually breaking into the user's account, then jacking up account privileges to the admin level.

There is a reason Windows allows anonymous access. In a trusted environment, this lets Windows NT, 2000, and XP machines see one another's shared folders and attached peripherals via the InterProcess communication share (IPC$). Allowing IPC$ is a must for some simple peer networks.

But IPC$ also allows entry to client machines. A hacker who types

net use \\yourcomputer\ipc$ "" /user:""
at a command line (where yourcomputer is either your internal IP address or your NetBIOS machine name) is assigned a blank name and password and connected to your PC. Establishing a null session like this does not allow control of your machine, but it does reveal all the user names on your system, the groups your system belongs to, the rights it has, and any shares available.

By setting or modifying a value in the Registry, you can restrict anonymous access. For Windows NT or 2000, go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa. Look in the right-hand pane for the DWORD value RestrictAnonymous. If you don't find it, right-click in the right-hand pane, choose Edit | New | DWORD Value, and name the value RestrictAnonymous.

In Windows NT with Service Pack 3 or in Windows 2000, the data for this value can be 0, 1, or 2 (we'll get to Windows XP in a moment). If it's 2, you're all set. No information can leak via a null session, because there is no way to establish one. If the value is 1 (all that was allowed before Windows NT with SP3), some tools can still enumerate information. If it is 0, your machine is wide open. Double-click on the value and set its data to 1 or 2, then restart the system.

Although 2 is preferable, it may cause connectivity and sharing problems when used outside of an environment running only Windows 2000. For example, down-level clients won't be able to establish access to the domain the Windows 2000 machine is hosting; that effectively closes those clients off from the network's resources.

Windows XP solves the problems that a setting of 2 can introduce by adding more flexibility to null-session restrictions. In addition to RestrictAnonymous, Windows XP has two other DWORD values you can modify—RestrictAnonymousSAM and EveryoneIncludesAnonymous. Set RestrictAnonymous to 1 to limit access to share information, and set RestrictAnonymousSAM to 1 to prevent enumeration of SAM accounts. Finally, assign EveryoneIncludesAnonymous a value of 0, which will keep null-session users from having any rights. This still allows the establishment of a null session, so basic network resources such as files and printers remain available to all trusted users, but nothing will leak.
APPLY SAFETY,PREVENT HACKING! :-)

Making passport size photographs and Printing them

2008-09-29T09:57:00.000-07:00

Making passport size photographs and Printing them
Photoshop Knowledge Required: Medium
Difficulty: Easy
External Plug-ins required: None

Before starting Reset your workspace by Window ---> Workspace ---> (Reset Palette Locations/Default Workspace)

If you have a decent printer and a picture of yours then you won't have to waste your bucks for getting your photos shot.
And it also comes in handy if there is an emergency situation and you need instant passport sized photographs.
So let's take this silhouette image as our sample. So we can concentrate on important things.

Now most of the passport images are in the ratio of 4:3. So we are going to crop this one like that too.

1) Select the rectangular Marquee Tool (M) and apply the following settings in it.

2) Now draw a rectangle in the image and place that it fits according to your needs.
Here is an example of what it should look like.

3) Image ---> Crop

Now the image is complete and ready for printing. But you may need multiple copies right?
And you might even need some borders to go with it?Okay here is how it is done.

Borders: (Can be skipped)
1) Press Ctrl+A to select the entire image.
2) Select ---> Modify ---> Border (Width: according you your needs)
3) Select the appropriate colour and hit Alt+Backspace. And you border is made.

Multiple Photos: (Shouldn't be more than four, this too can be skipped)
1) Press Ctrl+J the number of more pictures you want. E.g. I want four pictures and so I'll hit it three times.
2) Image ---> Canvas Size
(Now you have to increase the width of your canvas to the size of the pictures placed side by side, so a little mathematics is needed here)
If there are four copies then the approx width of the image should be 4*current size + some extra space for gaps.
I chose the width to be = 4*182+100 = 828

The canvas screen should look like this (except the size, because that is for you to calculate)

3) Now select the layers one by one in the layer's window and drag them to their appropriate positions.

Printing:
1) Press Alt+Ctrl+P
2) In the preview window, you can see how the print is going to look like.
3) Now what you have to do is set the image height, coz it's the same only the width has changed (If you have used the Multiple Photo option).
4) Set the image height to 4 cm. (This is the default size for photographs, you can set what you want), the width will automatically adjust.
5) Now you need to save paper too. We have to align the pictures to the top.
6) Deselect Center Image.
7) Set the top and left to 1 cm each.

And now you can print!

Note: If you need more that four pictures i.e. 8 then after printing once follow the last step again, instead increase the top and use the same paper to print. Just make sure that the images don't overlap.[/hide_me]

Hope you like my tutorial.
Comments are most welcome.

HOW TO HOST UR WEBSITE THROUGH UR COMPUTER

2008-09-29T09:42:00.000-07:00

Hosting a website on a static IP Internet connection

Note: Many Internet Service Providers that provide static IP addresses to their customers do not allow website hosting over these connections unless the customer opts for a specialized account. In our experience, personal websites often get overlooked when it comes to these regulations, but to be safe, check up on your provider's policies before you proceed further.

Provided your ISP allows it, hosting a website on a static IP connection is extremely easy. All you need to do is either register a domain (as covered above) and provide your static IP address as the target for the domain, or simply use your static IP address as a means to get to your web page.

If your IP should eventually change for some reason, simply updating your domain name with the new information or using the new IP address in your browser will suffice.

Using Dynamic DNS services to acquire a domain name for a static IP

If you read the section above on dealing with dynamic IP addresses, you will have noted that dynamic DNS services all provide you with a domain name by default. You can take advantage of this even if you have a static IP address. Sign up for the service, create your domain name and link it with your home PCs static IP address, either through the service's downloadable client or directly on their website. Presto, you have a domain name that people can type into a browser to reach your website.

Finally! Your own website.

If you've followed the above instructions carefully, you should be able to enter the domain name or IP address of your web server in any browser and be greeted with your brand new website. Congratulations! You now know enough to start delving deeper into the mysteries of IIS configuration. The IIS control panel can be accessed by right clicking 'my computer' and selecting 'manage', then expanding 'services and applications' and clicking on 'Internet Information Service'.

There are many, many control options here, which are beyond the scope of this article, but which we may delve deeper into in later guides. If you have any comments or questions, please post them in the PCSTATS Forums or drop us a line at the Feeback page.

Find out about this and many other reviews by joining the Weekly PCstats.com Newsletter today! Catch all of PCstats latest hardware reviews right here.

Beginners Guides: Website Hosting From A Home PC

Obstacles like IIS and dynamic IP addresses can make the process of running a website off a home broadband internet connection complicated... There are several tricks you'll need to know to get it working, so follow along and get clicking! - Version 1.0.0

Bookmark this PCstats guide for future reference.

Websites are still cool. It doesn't matter how many badly designed personal sites there are out there with questionable flash animations and animated GIFs abounding; the fact is that a website still offers you almost unlimited room for personal expression, with the added side-bonus of potentially being useful.

If you want a website badly enough, there are many service providers that will be only too willing to design the site for you, then host it on one of their servers for a monthly fee. If you have the cash, you can have a website of your own quickly and easily.

But what if you have the ideas but not the cash? Why pay someone else to host your website for you when you can easily do it yourself on the home computer over a broadband Internet connection?

In this guide, PCSTATS will explore the process of hosting a website from your home computer using a broadband Internet connection. For the sake of simplicity, we'll stick to using Microsoft's IIS (Internet Information Server) to render the site, and help you deal with the issues of dynamic IP addresses, among other potential home-based web hosting problems.

We'll leave the details of creating your own HTML website up to you. There are plenty of freely available programs that can help you do this, and of course you can always just use Notepad to code up the HTML by hand, so no excuses. We're only interested in the hard parts of hosting a website from a home PC!

Note: Since this PCSTATS beginner's guide only covers using Microsoft's IIS application to host websites, users of Windows XP Home edition or Windows 98SE/ME are out of luck. Unfortunately, IIS is not included with these operating systems. We may produce a guide on using a third-party web hosting program like Apache later on, depending on reader interest. For the purposes of this guide,Windows NT/2000/XP Professional will all work.

Before we get going, we need to get familiar with a few basic concepts, namely DNS (Domain Name System) and IP (Internet Protocol) addresses and how they are used when hosting a website. The following descriptions are slightly (or not so slightly) simplified, but they will suffice for our objective.

Understanding IP Addresses

IP (Internet Protocol) addresses are the backbone of computer networking, both on the Internet and in your home network. They are the 'phone numbers' that allow computers to locate and communicate with each other across networks.

An IP Address is made up of 4 sets of decimal numbers, 0-255, separated by periods (for example, 192.168.44.251) which form the address of a computer on the Internet or within a local network, and allow it to be referenced by other computers.

In order to view a website, or to allow others to view your website, your computer must have a valid Internet IP address in order to exchange data with a web server or the potential readers of your website.

Your Internet Service Provider allocates your home PC a valid Internet IP address when it connects to the Internet. Depending on the provider, this IP address may stay the same for long periods (static IP) or may change frequently (dynamic IP).

A computer can have multiple IP addresses assigned to it. If your computer connects both to the Internet via your provider's cable/DSL modem and to a home network, you will have a separate IP address for each connection.

To view your IP address information, go to 'start\run' and type 'cmd' to bring up the command prompt, then type 'ipconfig'. This will list all the IP addresses your computer is currently using. If you use a home router or other Internet sharing device, check its status page to find out your Internet IP address. If you are not sure how to do this, consult the manual for the device.

Understanding DNS

The Domain Name System puts a friendly face on the Internet. Let's put it this way... what's easier to remember: www.google.com or '64.233.161.104'? Right, we agree.

To your browser, the above two entries become one and the same thanks to the magic of DNS. What the system does is to map domain names like Goole.com to IP addresses like '64.233.161.104'.

For example, when you type

www.pcstats.com into your browser's address bar, the computer sends that address to a DNS server on your network or the Internet, looking to have it translated into an IP address that it can contact directly. That DNS server will send back the IP address if it knows it, and if it doesn't, it will contact other DNS servers all the way up to the root of the Internet until it finds the address it's looking for. The entire process generally takes less than a second.

Internet Service Providers generally assign each customers computer a DNS server to contact when the connection is first set up. If you are using a home Internet sharing device, it will receive DNS requests from your network and pass them on to the ISP's server. Without a DNS server, the web browser will be unable to transform domain names (URLs) like www.pcstats.com into IP addresses, and thus cannot access web pages.

DNS and Website Hosting

Technically, you don't NEED a domain name to host a website. If your home computer is connected to the Internet with IIS running, and you have created a web page (in a special folder), anyone on the internet can access that information by typing the IP address of your home computer into their web browser.

If you want to have a website that people will actually visit though, it's best to get a domain name, preferably a catchy one.

How do I get a DNS domain name for my website?

To get a domain name, you'll need to register your choice with one of the many, many domain name registration services. Network Solutions is the grandaddy of them all, but there are other independent companies which offer more competitive pricing on a yearly, or multi-yearly basis. It pays to do some research, and we would suggest choosing a domain name registration provider based in your native country if at all possible. A central body governs all domain names on the Internet, and the various registration services have acquired permission to lease them to you for a period of time, usually starting with a minimum of 2 years.

Once you have found a domain name registration service provider you like, the next issue is ensuring the domain name you've chosen is not already registered. It it is free, you can choose the extension (ie. .com, .org, .net, etc.) and register that name. The registrar will always run a search to see if the particular domain name you have chosen is already taken, so there is no chance of two individuals owning 'Google.com' for example. Fees will vary, but in all cases you are registering that domain name only for a certain length of time, measured in years.

Once you have registered your domain name, you can use the domain name registration service's tools to map it with your computer's IP address. From this point on, anyone who enters your domain name into a web browser will be directed to your IP address.

Domain names and websites

Do you have to register a domain to have a website?

No. The advantage of paying for a domain name is that you get to choose an easy and memorable word that people can type into their browsers to reach your website. Otherwise there are many free services that will cheerfully provide you with one of a limited set of domain names, and you can even just use your IP address as the way to contact your website (though this will not work if you have a dynamic IP connection, more on that below). We'll go into these services in more detail later in the article.

Static IP versus dynamic IP

If you want to host a website, you need to know whether your ISP assigns your PC a static (rarely changing) or dynamic IP address. Many cable-based ISPs provide static addresses, while most DSL providers use dynamic IP addresses which change every time your computer connects to the internet. There are exceptions to both of these rules though, so the best way is to contact your provider and ask. Alternately, you can monitor your IP address over the course of a couple of days of normal use (including connecting and disconnecting from the Internet if you are using DSL) to see if it changes.

A static IP address is very easy to host a website with, while dynamic addresses introduce a few more complexities. It's quite possible to do it either way though, so don't worry.

As above, to check your Internet IP address, sit at the computer your DSL or cable modem is connected to and go to 'start\run' and type 'cmd' to bring up the command prompt, then type 'ipconfig'.

If you use a router or Internet sharing device, go to the status menu to check it's current IP address. Make note of this IP number.

Part 2: Hosting a Website andInstalling IIS

Now let's get down to business. To host a website on your home PC, you will need to have Microsoft's IIS (Internet Information Server) installed on a Windows XP Professional or Windows NT/2000 system. There are other hosting programs out there, like Apache, but that is beyond the scope of this guide.

The first order of business is to make sure you have IIS installed. Go to 'control panel\add or remove programs'. Next, click the 'add/remove Windows components' button on the left.

From the new window, scroll down until you find 'Internet Information Services (IIS)'. Check this entry if necessary, then Double click it. If it is already checked this means IIS is installed on the computer.

Scroll to the bottom and ensure that the World Wide Web service is checked. Uncheck the SMTP and FTP service for now. Click OK, then OK again. If IIS was not previously installed, you will need to insert the original Windows Installation CD to install it now.

Patches and IIS Options

Hosting a website is essentially inviting strangers to poke around inside parts of your computer. While IIS prevents visitors to your web page from spilling over into the rest of your data, many security vulnerabilities exist in different versions of the program. To ensure maximum protection, visit the Windows Update website and download any security patches and updates that you may be missing.

Adding a website to IIS

Now that IIS is installed and patched, it's time to add your website. Open up 'my computer' or Explorer and navigate to your 'c:' drive. You should have a folder called 'inetpub'.

This is the folder where IIS expects all files for your web and FTP sites to be by default. Open up 'inetpub' and then the 'wwwroot' directory. This folder will hold the files for your first published website.

If you are creating a website from scratch, you can do so now. You should call the initial page of your site (the home page) 'index.htm' when you save it, as that is the file name that IIS expects to see as the primary HTML file. You can add all your HTML pages to the same WWWROOT directory, or create new directories under WWWROOT (or elsewhere) for them. Best practice is to place all files and directories (if needed) under WWWROOT.

If you have already created a website, rename the main HTML file to 'index.html' and copy your files to the 'c:\inetpub\WWWROOT\' directory. Since users coming to your website will not be able to move from the 'WWWROOT\' folder up to the Inetpub\ folder, the links to other webpages on your site should not include the 'C:\Inetpub\WWWROOT\' prefix. For example, a link in the index.html page to the secondpage.html file need only be of the form '', or ''. If you had incorrectly typed '' as the link, that would generate an error as being an unresolvable page.

Once your website files are created or copied into the WWWROOT folder, it's time to test to see if it is all working correctly. To do this, open up a web browser of your choice and type 'http://localhost/' in the address bar.

There's your website, ready for prime time. Please note that from your computer you can reach your website by using the address 'http://localhost' or '127.0.0.1'. This does not mean that anyone on the internet can use these two addresses to reach your website however - they are only internally addressable to your PCs WWWROOT folder.

Making a website Accessible from the Internet

The first thing we need to do is to prepare any firewall software or hardware that is currently guarding your system.

With the modern Internet's virus and malware-infested climate, just about every computer uses some form of firewall software or hardware. Since firewalls block all unsolicited incoming data by default, they can make it rather hard for people to view your website. In order to browse to your site on your home PC, potential readers must first send data through port 80 to IIS on your computer. Firewalls will block this incoming traffic, stopping your website from being accessed.

To get around this problem, you need to create an exception or virtual server. Depending on the type of firewall you use, this means one of several different processes. If you use a personal firewall like the Windows XP Frewall or Zonealarm, you need to authorize IIS to act as a server.

To do this in the pre-service Pack 2 version of the Windows XP Firewall, find your Internet connection by going to 'my network places' then 'show all connections.' Right click on your Internet connection's icon and hit 'properties' then 'settings'.

In the 'services' tab, scroll down until you see 'web server (HTTP)' and check its box.

In the post-SP2 version of the Windows XP Firewall, you can allow web traffic to pass through to IIS by going to 'start\control panel\windows firewall' then opening the 'advanced' tab.

Highlight your Internet connection in the 'network connection settings' window, then click 'settings.'

From this screen, place a checkmark in the HTTP box and hit 'ok.'

If you use an Internet sharing device like a home router as your firewall, you will need to create a virtual server (also known as port forwarding) to allow your website to be accessible over the Internet.

A virtual server is a set of instructions given to the home router, telling it that if data comes in over a specific port (say TCP port 80 for hosting a website) that data should be allowed through the firewall and forwarded to a specific computer inside the network. In this way, you can make your website (or whatever else) available without otherwise compromising your firewall security.

Creating a virtual server tends to be the same in almost all home router models. First consult your documentation to find the configuration page for 'virtual servers' or the equivalent.

When creating a virtual server, you will need to first enter the IP address of the computer that is hosting the website. Next you need the port that data enters that system on. Enter TCP port 80, since this is the default port for HTTP.

Finally, you need to choose the port that will be open on the router to receiver the data. In most cases, this will be the same as the port on your hosting computer, so enter 80 here too.

Once you save this information, all data coming from the Internet to the firewall on TCP port 80 will be allowed through the firewall and redirected to your hosting computer, thus allowing access to your website.

Now that your firewall is going to allow web traffic into your computer, let's take a look at how to prepare your website for using either a static or dynamic IP from your broadband internet service provider. Depending on your connection type, just go to the appropriate page below

Hosting a website on a dynamic IP Internet connection

Most DSL broadband internet service providers and many cable companies change the IP addresses of their customers frequently. In the case of DSL, the change generally occurs each time the customer connects to the Internet, while with cable, the changes can occur at any point.

It might seem impossible to host a web site from an IP address that potentially changes every day, but it can actually be done quite easily through the magic of dynamic DNS.

What is Dynamic DNS?

Dynamic DNS services provide their clients with a DNS address (as covered above) and install a small application on the client's computer which monitors its current ISP-designated IP address. When that IP address changes, the application alerts the dynamic DNS provider who then updates the client's DNS records with the new IP. In this way, visitors who try to access the client's web site using his DNS address will always be directed to the right IP address, no matter how many times a day it changes.

Several companies offer free dynamic DNS service over the Internet. Generally speaking, you sign on for a free membership and pick a DNS name from the ones the company has on offer. This does provide you with limited options for personalizing the address of your website, since most dynamic DNS companies will only allow you to customize the 'server' part of the address they give you. For example, you might be presented with '*****.sytes.net' and be allowed to customize the asterisked portion.

Fortunately, most domain registration services allow you to redirect your registered DNS name to another DNS name. This means you can register the domain name of your choice then redirect it to your yourwebsite.sytes.net dynamic DNS address, which then redirects visitors to your constantly updated IP address. Neat.

To set this up, you'll first have to register with a dynamic DNS provider. Some of the more popular free dynamic DNS sites are DynDNS.org and No-IP.com, but there are many, many more. Here's a list to get you started.

In most cases, the dynamic DNS provider will lead you through the process of setting up dynamic DNS, which includes choosing a domain name from the provider and downloading and installing their client software. There are several other options that dynamic DNS providers may offer, such as aliases (which allow you to map multiple domain names to your computer's IP address) and MX records for email, but we're not going to cover these in detail in this guide.

Once the dynamic DNS is all set up, test it by opening up a web browser and entering the domain name you got from the dynamic DNS provider. Provided your web site is up and running in IIS, you will now be seeing your website from across the Internet.

Now all you have to do is ensure that the dynamic DNS update program you downloaded from the provider is running at all times, and anyone will be able to access your website from the Internet.

Hosting a website on a static IP Internet connection

If your IP should eventually change for some reason, simply updating your domain name with the new information or using the new IP address in your browser will suffice.

Using Dynamic DNS services to acquire a domain name for a static IP

Finally! Your own website.

Find out about this and many other reviews by joining the Weekly PCstats.com Newsletter today! Catch all of PCstats latest hardware reviews right here.

How to find if someone is invisible on Gtalk / Gmail chat

2008-09-29T09:41:00.001-07:00

How to find if someone is invisible on Gtalk / Gmail chat

I discovered a bug in Google Talk’s invisible status feature available in its Gmail Chat version and Gtalk Lab Edition version. If use smartly, you can figure out if some is avoiding you or really offline.

Here are steps:

Set the chat as off the record with target user (how?). This can be done only when the other user is online. (need help?)
Now try sending chat to that user when he is invisible or offline.
If he is invisible, then he will receive chat.
But if he Is offline, then you will receive error “ did not receive your chat”.

Explanation:

Point 1: When a chat is set off the record, it will no longer get stored in your Gmail account.

Point 2: When you send a chat message to offline or invisible user, it gets delivered by default. At receiving end if user is online, a chat screen pops up showing him your message. If he is offline, your chat message will go to inbox as a mail.

Now if you put together above points then you will notice that, when you set chat off the record it can’t be delivered to inbox as mail, so it will be delivered only if user is online (no matter if he is invisible).

Now the only tricky part is finding a user online for once to set chat off the records. This doesn’t seem hard as invisible status is still limited to Gmail version of Google Talk and you may be in luck if your friend uses Google Talk desktop clients/gadgets or third party IM client to chat.

2008-09-29T09:39:00.000-07:00

Hack DNS for lightning-fast Web browsing

Here are no-cost ways to fine-tune DNS for faster browsing

Preston Gralla

May 23, 2007 (Computerworld) No matter how big the broadband pipe you use to surf the Web, it's not big enough. Everyone, whether they use a slowpoke dial-up modem or the fastest FiOS line, wants to surf faster.

There's a simple way you can get to Web sites faster, and it won't cost you a penny. You can hack the way your PC uses the Domain Name System (DNS), the technology underlying all Web browsing. It's far simpler to do than you might imagine, as you'll see in this article.

Understanding DNS

Before you start, it's a good idea to get a basic understanding of how DNS works. When you type in a URL such as www.computerworld.com, that URL needs to be translated into a numeric IP address that Web servers and Internet routers can understand. When you type in a URL, a DNS server does the translation, from www.computerworld.com to 65.221.110.98, for example.

DNS servers live on the Internet, and your computer contacts them with the request to do that translation, which is commonly called name resolution. When you use an ISP, your computer will automatically use the default DNS servers specified by your ISP; you typically don't need to set up DNS in any way. If you're on a corporate network, your systems administrator may have set you up to use specific DNS servers.

If there's a delay in contacting the DNS server, or if the DNS server takes too much time resolving the address, you'll face a delay in getting to a Web site. So even if you've got the world's fattest pipe, your Web surfing will be slowed down.

If you could speed up the name resolution in some way, you'd be able to speed up your Web surfing. And that's exactly what I'll show you how to do.

Speed up Web browsing with OpenDNS

Here's the simplest way to hack DNS to speed up your Web browsing: Use free, superfast DNS servers run by the OpenDNS service instead of your ISP's DNS servers. OpenDNS has a monstrously big DNS cache, with DNS servers around the world, so you'll be able to retrieve IP addresses from it more quickly than from your ISP's DNS servers.

As I'll explain a little later in this article, the service includes other benefits as well, such as letting you create browser shortcuts so that you could go to www.computerworld.com, for example, by just typing the letter c in your browser and pressing Enter.

The addresses of the OpenDNS servers are 208.67.222.222 for a primary DNS server and 208.67.220.220 for a secondary server.

To use the OpenDNS servers, you'll have to tell your computer to use them. If you have Windows XP, first select Control Panel --> Network and Internet Connections --> Network Connections, right-click your network connection from the Network Connections window, and select Properties. A dialog box like that shown below appears.


Highlight the Internet Protocol (TCP/IP) listing and select Properties in order to get to a dialog box that will let you use OpenDNS server. (Click image to see larger view.)

Scroll down to the Internet Protocol (TCP/IP) listing and select Properties. At the bottom of the screen, select "Use the following DNS server addresses." For the Preferred DNS server, enter this address: 208.67.222.222. For the Alternative DNS server, enter this address: 208.67.220.220. Click OK, and then click Close and Close again. Restart your PC in order for the settings to take effect. The figure below shows the screen filled out properly.


	Telling your PC to use the OpenDNS servers. (Click image to see larger view.)

If you're using Windows Vista, select Control Panel --> Network and Internet --> Network and Sharing Center. Click the View Status link on the right side of the screen. The Local Connection Status screen appears, as shown in the figure below. Click Properties.


	Click Properties in order to get to a dialog box that will let you use OpenDNS servers. (Click image to see larger view.)

You'll come to the same dialog box as you would for XP that lets you use the OpenDNS servers. Follow the same directions as for using OpenDNS on XP, and you'll be set.

When you configure a PC to use OpenDNS, only that PC will be able to use the OpenDNS servers. If you want all of the PCs on your network to use the servers, you can tell your router to use the OpenDNS servers, and then all of your PCs on the network will follow suit. That way, you won't have to configure each individual PC.

The way you do this will vary from router to router, and it changes according to whether you're using a router for a home office/small office or a larger corporate router. For a small office/home office router, you'll log into your router, look for the DNS settings, and then use the OpenDNS settings of 208.67.222.222 for the primary DNS server and 208.67.220.220 for the alternative DNS server.

Whether you run a small network or larger network, you can get benefits beyond faster DNS. The service also gives you DNS management tools such as domain blocking. It also gives you statistics and charts about your network's DNS use.

On Linksys SRX 400 and many other Linksys routers, log into your router by going to the log-in page at 192.1681.1, using admin as the password and leaving the username blank. Scroll down the page until you come to the Static DNS 1 and Static DNS 2, as shown in the figure below. Click Save Settings. Restart your router and the PCs on your network, and they will begin using the OpenDNS DNS servers.


	Change the DNS settings on this screen to use the OpenDNS servers for your entire network. (Click image to see larger view.)

If you run a corporate network and need help getting it set up, your best bet is to go to the OpenDNS FAQ page.

Note that OpenDNS may not work when using a virtual private network. For example, I wasn't able to get it to work using a Cisco VPN. And if you're on a corporate network, you should check with your systems administrator before using OpenDNS.

OpenDNS also lets you create shortcuts that let you visit Web sites by typing in a letter or group of letters instead of a full URL. To do that, you'll first need to register, which is free. After you do that, go to the site, log in, and click the Shortcuts link. On the page that appears, type in the shortcut text in the top box, and the URL in the bottom box and click Create Shortcut. From now on, when you type the shortcut text into your browser window, you'll be sent to the full URL.

You can also add the OpenDNS bookmarklet (found at the bottom of the page) to your browser and, in that way, create a shortcut no matter where you are on the Internet.


	Creating a shortcut in OpenDNS. (Click image to see larger view.)

Speed up Web access with a HOSTS file

There's another way to speed up DNS -- by creating or editing a local HOSTS file on your own PC that contains URLs (also called hostnames) and their corresponding IP addresses. Windows will first look there to see whether there's an entry for the hostname, and if it finds it, it will resolve the address itself. That way, you won't have to go out to a DNS server and wait for the response before visiting a Web site.

The HOSTS file is a plain-text file you can create or edit with a text editor like Notepad. You should find an existing HOSTS file in C:\Windows\System32\Drivers\Etc\HOSTS in both Windows XP and Windows Vista. (In some versions of Windows, it may be located in C:\Winnt\System32\Drivers\HOSTS). The file has no extension; it is named only HOSTS. If you don't find one, create it in Notepad.

Open the HOSTS file in Notepad and enter the IP addresses and hostnames of your commonly visited Web sites, like this:
65.221.110.98 computerworld.com

Each entry in the file should be on one line. The IP address should be in the first column, and the corresponding hostname in the next column. At least one space should separate the two columns. When you're finished editing the file, save it to its existing location.

Make sure to check your HOSTS file regularly and keep it up-to-date, or else you might deny yourself access to certain Web sites. For example, if www.computerworld.com were to change its IP address but your HOSTS file kept the old, incorrect address, your browser would not be able to find the site.

Adjust Windows' DNS cache

To speed up DNS, Windows puts the DNS information into a local DNS cache on your PC when you visit a site. So when you want to go to a site, Windows first looks in its local DNS cache, called the resolve cache, to see whether the DNS information is contained there. That way, if it finds the information locally, it doesn't have to look in your HOSTS file or query a remote DNS server to find IP information. The cache is made up of recently queried names and entries taken from your HOSTS file.

The cache contains both negative and positive entries. Positive entries are those in which the DNS lookup succeeded and you were able to connect to the Web site. When Windows looks in the cache, if it finds a positive entry, it immediately uses that DNS information and sends you to the requested Web site.

Negative entries are those in which no match was found, and you end up getting a "Cannot find server or DNS" error in your browser. Similarly, when Windows looks in the cache and finds a negative entry, it gives you the error message without bothering to go out to the site.

Negative entries can lead to problems. When you try to make a connection to a site that has a negative entry in your cache, you'll get an error message, even if the site's problems have been resolved and it's now reachable.

You can solve this problem, though, using a Registry hack. By default, Windows caches negative entries for five minutes. After five minutes, they're cleared from your cache.

But if you'd like, you can force Windows not to cache these negative entries so that you'll never run into this problem. Run the Registry Editor by typing Regedit at a command prompt or the Windows Vista search box, and press Enter. Then go to

HKEY_LOCAL_MACHINE\SYSTEM
\CurrentControlSet\Services\Dnscache
\Parameters

Create a new DWORD value with the name NegativeCacheTime and give it a value of 0. (The value might already exist. If it does, edit its value to 0.)

The DWORD determines how much time, in seconds, to keep negative entries in the DNS cache. If you like, you can have the entries stay alive for one second by giving the DWORD a value of 1.

After you're done editing, exit the Registry. To make the change take effect, restart your computer, or flush your cache by issuing the command ipconfig /flushdns at a command prompt. The command will flush your DNS cache -- all the entries, both positive and negative, will be flushed -- and it will be empty until you start visiting Web sites. Negative entries, however, will not be added to the cache if you've given the DWORD a value of 0.

You can also use the Registry to control the amount of time positive entries are kept in the DNS cache. By default, they are kept for 24 hours. To change the default, go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters again and create a DWORD value called MaxCacheEntryTtlLimit. (If it's already present, just edit the value.) For the value, enter the amount of time you want the entry to remain, in seconds, making sure to use decimals as the base.

If you run into other DNS problems, see the related story, "Fix your DNS problems."

Get unlimited bandwidth from your host for free

2008-09-29T09:38:00.000-07:00

Get unlimited bandwidth from your host for free

NOTE: This applies only to specific hosting companies, due to thespecific setup needed and does have its drawbacks.While setting up hosting space with a specific company I often dealwith, I noticed that they used a shared IP. (IP shared by two or morewebsites/domains.) Well, the rates for unlimited bandwidth werearound $50+ per month, which I found unreasonable. I didnt requiremuch space, and didnt want to be limited to a mere 3 gig of trafficper month.Back on track… When setting up the acct, the hosting company needsto know the domain name so that they can direct it accordingly.(example: ‘http://www.123.4.567.890/~user1/ ,’http://www.123.4.567.890/~user2/ etc)At this point you can give a url that doesnt belong to you at all. Aslong as the nameservers dont change, that should have absolutly nonegative effects on you or your site whatsoever.How it works is this:The host propogates you a certain amount space on its servers, andmonitors the traffic that enters their space through the domain itsregistered under. Being that the domain isn’t connected to the siteat all, it registers ZERO traffic.Zero traffic registered = can’t possibly go over bandwidthrestrictionscan’t possibly go over bandwidth restrictions = free unlimitedbandwidthNow the problems with this (besides the ethical ones) is that yourhost may offer X amount of mail addys with the acct(you@y…) and these will not work, as the name isnt on theirDNS. However, some domain companies allow you to set it upregardless. Another problem seems to be strictly cosmetic, but can behighly problematic… Once you attach the domain you want onto thesite, each page comes up/w the ip/UN the host propagated to youracct. Its at this point where you have to have a phenominal 10-15character alphanumerical or better (#, &, etc) pw, or your site willbe vulnerable to attack since the attacker already has your UN. Thisonly gives attackers a slight advantage as the amount of time itwould take to brute force a 10 character pw @ a rate of 1,000,000 persecond is 10 years. Add numbers and case sensitivity to that and itbecomes approx 26,980 years.While I’m on it, I may as well add that if you use this method,obviously you are going to be using the lowest cost hosting planavailable, which in turn will offer the least amount of space. Thatswhy free hosts were invented.Free hosts suck as a general rule. Who wants a site smothered in ads?However, if you upload all your programs, graphics and other largefiles (have a backup of course) to a reliable free host and targetthem accordingly from your site you have just freed up a signifigantamount of space. The only setback/w this is having to keep an indexcard or file around/w your pws, as you should never use the same onetwice, and want to use complicated ones.

All About FTP

2008-09-29T09:35:00.000-07:00

Well, since many of us have always wondered this, here it is. Long and drawn out. Also, before attempting this, realize one thing; You will have to give up your time, effort, bandwidth, and security to have a quality ftp server.
That being said, here it goes. First of all, find out if your IP (Internet Protocol) is static (not changing) or dynamic (changes everytime you log on). To do this, first consider the fact if you have a dial up modem. If you do, chances are about 999 999 out of 1 000 000 that your IP is dynamic. To make it static, just go to a place like

Code:

http://www.myftp.org/

to register for a static ip address.

You'll then need to get your IP. This can be done by doing this:
Going to Start -> Run -> winipcfg or www.ask.com and asking 'What is my IP?'

After doing so, you'll need to download an FTP server client. Personally, I'd recommend G6 FTP Server, Serv-U FTPor Bullitproof v2.15 all three of which are extremely reliable, and the norm of the ftp world.
You can download them on this site:

Code:

http://www.liaokai.com/softw_en/d_index.htm

First, you'll have to set up your ftp. For this guide, I will use step-by-step instructions for G6. First, you'll have to go into 'Setup -> General'. From here, type in your port # (default is 21). I recommend something unique, or something a bit larger (ex: 3069). If you want to, check the number of max users (this sets the amount of simultaneous maximum users on your server at once performing actions - The more on at once, the slower the connection and vice versa).

The below options are then chooseable:
-Launch with windows
-Activate FTP Server on Start-up
-Put into tray on startup
-Allow multiple instances
-Show "Loading..." status at startup
-Scan drive(s) at startup
-Confirm exit

You can do what you want with these, as they are pretty self explanatory. The scan drive feature is nice, as is the 2nd and the last option. From here, click the 'options' text on the left column.

To protect your server, you should check 'login check' and 'password check', 'Show relative path (a must!)', and any other options you feel you'll need. After doing so, click the 'advanced' text in the left column. You should then leave the buffer size on the default (unless of course you know what you're doing ), and then allow the type of ftp you want.

Uploading and downloading is usually good, but it's up to you if you want to allow uploads and/or downloads. For the server priority, that will determine how much conventional memory will be used and how much 'effort' will go into making your server run smoothly.

Anti-hammering is also good, as it prevents people from slowing down your speed. From here, click 'Log Options' from the left column. If you would like to see and record every single command and clutter up your screen, leave the defaults.

But, if you would like to see what is going on with the lowest possible space taken, click 'Screen' in the top column. You should then check off 'Log successful logins', and all of the options in the client directry, except 'Log directory changes'. After doing so, click 'Ok' in the bottom left corner.

You will then have to go into 'Setup -> User Accounts' (or ctrl & u). From here, you should click on the right most column, and right click. Choose 'Add', and choose the username(s) you would like people to have access to.

After giving a name (ex: themoonlanding), you will have to give them a set password in the bottom column (ex: wasfaked). For the 'Home IP' directory, (if you registered with a static server, check 'All IP Homes'. If your IP is static by default, choose your IP from the list. You will then have to right click in the very center column, and choose 'Add'.

From here, you will have to set the directory you want the people to have access to. After choosing the directory, I suggest you choose the options 'Read', 'List', and 'Subdirs', unless of course you know what you're doing . After doing so, make an 'upload' folder in the directory, and choose to 'add' this folder seperately to the center column. Choose 'write', 'append', 'make', 'list', and 'subdirs'. This will allow them to upload only to specific folders (your upload folder).

Now click on 'Miscellaneous' from the left column. Choose 'enable account', your time-out (how long it takes for people to remain idle before you automatically kick them off), the maximum number of users for this name, the maximum number of connections allowed simultaneously for one ip address, show relative path (a must!), and any other things at the bottom you'd like to have. Now click 'Ok'.
**Requested**

From this main menu, click the little boxing glove icon in the top corner, and right click and unchoose the hit-o-meter for both uploads and downloads (with this you can monitor IP activity). Now click the lightning bolt, and your server is now up and running.

Post your ftp info, like this:

213.10.93.141 (or something else, such as: '
Code:

ftp://example.getmyip.com

')

User: *** (The username of the client)

Pass: *** (The password)

Port: *** (The port number you chose)

So make a FTP and join the FTP section

Section 2: Error Messages

The File Transfer Protocol (FTP), as its name states, is a set of rules that dictates how files should be transfered over the TCP/IP protocol. A basic FTP connection consists of a client and a server. The client gets a file by opening a connection to the server. Usually, the server is run on port 21, however, the system administrator can change this if he or she wishes.

Once the client has connected to the server, the server will send a greeting to the client. A greeting usually looks something like the following:

220 SpiderMan's FTP server. Please login!

The number before the text is known as a completion code. The server greeting will be one of two codes: 220 if the server accepts the connection or 421 if the server rejects the connection.

After the server has sent its greeting, the client sends a request. A request is made up of a verb and, for some verbs, a parameter. Common verbs are:

Verbs Description
CWD Change the current directory on the server.
PWD Print the current directory on the server.
CDUP Moves up to the parent directory.
LIST List the contents of a directory.
MKD Creates a directory on the server.
RMD Removes a directory from the server.
DELE Removes a file from the server.
USER Sends the username for the login.
PASS Sends the password for the login.
ABOR Abort the transfer.
QUIT Closes the connection with the server.
STAT Gets the current status of the server.
TYPE Toggles the binary flag on the server.
PORT Asks the server to connect to the client.
PASV Requests a data connection on a new port.
RETR Requests the server to send a file.
STOR Sends a file from the client to the server
APPE Same as STOR, except data is appended.
REST Start a download at a certain position.
SYST Gets the OS information of the server.
HELP Get help on a verb.
NOOP No operation.

After sending a request, the client should wait for the server to respond before the client sends another request; however, the client can send an ABOR, STAT, or QUIT request without waiting for the server to respond. Typically, after the server has sent the greeting, the client will respond with a USER request in which the client sends the username to log into the FTP server with.

After the client has sent the server a request, the server replies with a response. A response consists of a completion code followed by one, or more, lines. Generally, if the second digit of the completion code is a 0, it is a syntax error message; if the second digit of the completion code is a 2, it is a hello or goodbye message.

Once the client is logged in, he or she would then get the file he or she wishes to retrieve. A typical session would look similar to this:

220 SpiderMan's FTP server. Please login!
USER SpiderMan
331 Username okay. Send password!
PASS password
230 Password accepted, user logged in.
LIST
150 Opening ASCII mode data connection for /bin/ls
226 Transfer complete
TYPE I
200 Type set to I
PASV
227 Entering passive mode (206,84,161,87,28,46)
RETR datafile.zip
150 Opening BINARY mode data connection for datafile.zip
226 Transfer complete

When downloading a file, the client should specify whether he or she wants the file sent in ASCII mode (each line ended with a CR/LF) or binary mode. To set the mode of transfer, the client sends the TYPE request. TYPE I would set the binary mode. By default, binary mode is turned off. It is important that the server send the file in the correct mode to avoid file corruption.

I should elaborate on the PASV and PORT request since they are very important to FTP. You may be wondering just what the PASV request is used for and what the odd looking response from the server is supposed to mean. When the client sends a PASV request, the server opens up a temporary socket and sends a reply to the client which informs the client of port to connect to. The reply would look like this:

PASV
227 Entering passive mode (206,84,161,87,28,46)

The numbers in the parentheses play an important role. The numbers separated by the first four commas make up the IP address to connect to. In this example, the IP would be 206.84.161.87. The remaining numbers specify which port to connect to. Usually, this is done by multiplying the first number by 256 and adding the second number. In this example, the port number would be 7214 (28*256+46= 7214). Now that the server has replied to the PASV request, two channels are open: the first (the original one) is the communication channel where the requests are sent and the second is the data channel where the data is transfered.

The PORT request is similar to the PASV request, however, when the client sends a PASV request, the server opens another socket and the client connects to it. When a client sends a PORT request, the server connects to the clientâ€”usually on port 20.

With the advent of IPv6, you may be wondering how FTP will be carried out since the servers are replying to the PASV requests with an IPv4 IP. One solution, proposed by D. Bernstein, would be to have IPv6 servers send a nonexistent IP address and have IPv6 clients ignore the IP and skip straight to the port number. This way, older clients using IPv4 will connect to a fake IP and give up trying to connect to the server.

Now that you know how FTP works, I'll show you how to log into a server, look around, and then get a file. Before I begin, I should tell you about anonymous FTP servers. An anonymous FTP server is just like a normal server, however, you can login using the username â€œanonymousâ€ and an e-mail as the password. In this example, I'll use a fake e-mail of guest@guest.com . Most anonymous FTP servers only read up to the @ sign, so if you're lazy you can just type in â€œguest@â€. A lot of sites offer anonymous FTP because it is an easy way to let the public get files without assigning each person a login. On with the example!

First, I connect to the server and send my username and password.

220 SpiderMan's FTP server. Please login!
USER anonymous
331 Anonymous login okay, send e-mail as password.
PASS guest@guest.com
230 Password accepted, logged in as anonymous.

Now that I'm in, I'll change to the â€œfilesâ€ directory and download a file.

CWD ./files
250 CWD command successful.
TYPE I
200 Type set to I
PASV
227 Entering passive mode (210,52,165,168,15,26)
RETR code.zip
150 Opening BINARY mode data connection for code.zip
226 Transfer complete

I've got the file I want, now I'll move up to the parent directory, move to another directory, and download another file.

CWD ..
250 Okay
CWD ./jokes
250 CWD command successful.
TYPE A
200 Type set to A
PASV
227 Entering passive mode (210,52,165,168,15,26)
RETR jokes.txt
150 Opening ASCII mode data connection for jokes.txt
226 Transfer complete

I got the two files I wanted, so now I'll logout.

QUIT
221 Goodbye, please come back!

110 Restart marker reply. In this case, the text is exact and not left to the particular implementation; it must read: MARK yyyy = mmmm Where yyyy is User-process data stream marker, and mmmm server's equivalent marker (note the spaces between markers and "=").
120 Service ready in nnn minutes.
125 Data connection already open; transfer starting.
150 File status okay; about to open data connection.
200 Command okay.
202 Command not implemented, superfluous at this site.
211 System status, or system help reply.
212 Directory status.
213 File status.
214 Help message. On how to use the server or the meaning of a particular non-standard command. This reply is useful only to the human user.
215 NAME system type. Where NAME is an official system name from the list in the Assigned Numbers document.
220 Service ready for new user.
221 Service closing control connection. Logged out if appropriate.
225 Data connection open; no transfer in progress.
226 Closing data connection. Requested file action successful (for example, file transfer or file abort).
227 Entering Passive Mode (h1,h2,h3,h4,p1,p2).
230 User logged in, proceed.
250 Requested file action okay, completed.
257 "PATHNAME" created.
331 User name okay, need password.
332 Need account for login.
350 Requested file action pending further information.
421 Too many users logged to the same account
425 Can't open data connection.
426 Connection closed; transfer aborted.
450 Requested file action not taken. File unavailable (e.g., file busy).
451 Requested action aborted: local error in processing.
452 Requested action not taken. Insufficient storage space in system.
500 Syntax error, command unrecognized. This may include errors such as command line too long.
501 Syntax error in parameters or arguments.
502 Command not implemented.
503 Bad sequence of commands.
504 Command not implemented for that parameter.
530 Not logged in.
532 Need account for storing files.
550 Requested action not taken. File unavailable (e.g., file not found, no access).
551 Requested action aborted: page type unknown.
552 Requested file action aborted. Exceeded storage allocation (for current directory or dataset).
553 Requested action not taken. File name not allowed.

Section 3: active Vs Passive
Active FTP vs. Passive FTP, a Definitive Explanation

Introduction
One of the most commonly seen questions when dealing with firewalls and other Internet connectivity issues is the difference between active and passive FTP and how best to support either or both of them. Hopefully the following text will help to clear up some of the confusion over how to support FTP in a firewalled environment.

This may not be the definitive explanation, as the title claims, however, I've heard enough good feedback and seen this document linked in enough places to know that quite a few people have found it to be useful. I am always looking for ways to improve things though, and if you find something that is not quite clear or needs more explanation, please let me know! Recent additions to this document include the examples of both active and passive command line FTP sessions. These session examples should help make things a bit clearer. They also provide a nice picture into what goes on behind the scenes during an FTP session. Now, on to the information...

The Basics
FTP is a TCP based service exclusively. There is no UDP component to FTP. FTP is an unusual service in that it utilizes two ports, a 'data' port and a 'command' port (also known as the control port). Traditionally these are port 21 for the command port and port 20 for the data port. The confusion begins however, when we find that depending on the mode, the data port is not always on port 20.

Active FTP
In active mode FTP the client connects from a random unprivileged port (N > 1024) to the FTP server's command port, port 21. Then, the client starts listening to port N+1 and sends the FTP command PORT N+1 to the FTP server. The server will then connect back to the client's specified data port from its local data port, which is port 20.

From the server-side firewall's standpoint, to support active mode FTP the following communication channels need to be opened:

FTP server's port 21 from anywhere (Client initiates connection)
FTP server's port 21 to ports > 1024 (Server responds to client's control port)
FTP server's port 20 to ports > 1024 (Server initiates data connection to client's data port)
FTP server's port 20 from ports > 1024 (Client sends ACKs to server's data port)

In step 1, the client's command port contacts the server's command port and sends the command PORT 1027. The server then sends an ACK back to the client's command port in step 2. In step 3 the server initiates a connection on its local data port to the data port the client specified earlier. Finally, the client sends an ACK back as shown in step 4.

The main problem with active mode FTP actually falls on the client side. The FTP client doesn't make the actual connection to the data port of the server--it simply tells the server what port it is listening on and the server connects back to the specified port on the client. From the client side firewall this appears to be an outside system initiating a connection to an internal client--something that is usually blocked.

Active FTP Example
Below is an actual example of an active FTP session. The only things that have been changed are the server names, IP addresses, and user names. In this example an FTP session is initiated from testbox1.slacksite.com (192.168.150.80), a linux box running the standard FTP command line client, to testbox2.slacksite.com (192.168.150.90), a linux box running ProFTPd 1.2.2RC2. The debugging (-d) flag is used with the FTP client to show what is going on behind the scenes. Everything in red is the debugging output which shows the actual FTP commands being sent to the server and the responses generated from those commands. Normal server output is shown in black, and user input is in bold.

There are a few interesting things to consider about this dialog. Notice that when the PORT command is issued, it specifies a port on the client (192.168.150.80) system, rather than the server. We will see the opposite behavior when we use passive FTP. While we are on the subject, a quick note about the format of the PORT command. As you can see in the example below it is formatted as a series of six numbers separated by commas. The first four octets are the IP address while the second two octets comprise the port that will be used for the data connection. To find the actual port multiply the fifth octet by 256 and then add the sixth octet to the total. Thus in the example below the port number is ( (14*256) + 178), or 3762. A quick check with netstat should confirm this information.

testbox1: {/home/p-t/slacker/public_html} % ftp -d testbox2
Connected to testbox2.slacksite.com.
220 testbox2.slacksite.com FTP server ready.
Name (testbox2:slacker): slacker
---> USER slacker
331 Password required for slacker.
Password: TmpPass
---> PASS XXXX
230 User slacker logged in.
---> SYST
215 UNIX Type: L8
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ls
ftp: setsockopt (ignored): Permission denied
---> PORT 192,168,150,80,14,178
200 PORT command successful.
---> LIST
150 Opening ASCII mode data connection for file list.
drwx------ 3 slacker users 104 Jul 27 01:45 public_html
226 Transfer complete.
ftp> quit
---> QUIT
221 Goodbye.

Passive FTP
In order to resolve the issue of the server initiating the connection to the client a different method for FTP connections was developed. This was known as passive mode, or PASV, after the command used by the client to tell the server it is in passive mode.

In passive mode FTP the client initiates both connections to the server, solving the problem of firewalls filtering the incoming data port connection to the client from the server. When opening an FTP connection, the client opens two random unprivileged ports locally (N > 1024 and N+1). The first port contacts the server on port 21, but instead of then issuing a PORT command and allowing the server to connect back to its data port, the client will issue the PASV command. The result of this is that the server then opens a random unprivileged port (P > 1024) and sends the PORT P command back to the client. The client then initiates the connection from port N+1 to port P on the server to transfer data.

From the server-side firewall's standpoint, to support passive mode FTP the following communication channels need to be opened:

FTP server's port 21 from anywhere (Client initiates connection)
FTP server's port 21 to ports > 1024 (Server responds to client's control port)
FTP server's ports > 1024 from anywhere (Client initiates data connection to random port specified by server)
FTP server's ports > 1024 to remote ports > 1024 (Server sends ACKs (and data) to client's data port)

In step 1, the client contacts the server on the command port and issues the PASV command. The server then replies in step 2 with PORT 2024, telling the client which port it is listening to for the data connection. In step 3 the client then initiates the data connection from its data port to the specified server data port. Finally, the server sends back an ACK in step 4 to the client's data port.

While passive mode FTP solves many of the problems from the client side, it opens up a whole range of problems on the server side. The biggest issue is the need to allow any remote connection to high numbered ports on the server. Fortunately, many FTP daemons, including the popular WU-FTPD allow the administrator to specify a range of ports which the FTP server will use. See Appendix 1 for more information.

The second issue involves supporting and troubleshooting clients which do (or do not) support passive mode. As an example, the command line FTP utility provided with Solaris does not support passive mode, necessitating a third-party FTP client, such as ncftp.

With the massive popularity of the World Wide Web, many people prefer to use their web browser as an FTP client. Most browsers only support passive mode when accessing ftp:// URLs. This can either be good or bad depending on what the servers and firewalls are configured to support.

Passive FTP Example
Below is an actual example of a passive FTP session. The only things that have been changed are the server names, IP addresses, and user names. In this example an FTP session is initiated from testbox1.slacksite.com (192.168.150.80), a linux box running the standard FTP command line client, to testbox2.slacksite.com (192.168.150.90), a linux box running ProFTPd 1.2.2RC2. The debugging (-d) flag is used with the FTP client to show what is going on behind the scenes. Everything in red is the debugging output which shows the actual FTP commands being sent to the server and the responses generated from those commands. Normal server output is shown in black, and user input is in bold.

Notice the difference in the PORT command in this example as opposed to the active FTP example. Here, we see a port being opened on the server (192.168.150.90) system, rather than the client. See the discussion about the format of the PORT command above, in the Active FTP Example section.

testbox1: {/home/p-t/slacker/public_html} % ftp -d testbox2
Connected to testbox2.slacksite.com.
220 testbox2.slacksite.com FTP server ready.
Name (testbox2:slacker): slacker
---> USER slacker
331 Password required for slacker.
Password: TmpPass
---> PASS XXXX
230 User slacker logged in.
---> SYST
215 UNIX Type: L8
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> passive
Passive mode on.
ftp> ls
ftp: setsockopt (ignored): Permission denied
---> PASV
227 Entering Passive Mode (192,168,150,90,195,149).
---> LIST
150 Opening ASCII mode data connection for file list
drwx------ 3 slacker users 104 Jul 27 01:45 public_html
226 Transfer complete.
ftp> quit
---> QUIT
221 Goodbye.

Summary
The following chart should help admins remember how each FTP mode works:

Active FTP :
command : client >1024 -> server 21
data : client >1024 <- server 20

Passive FTP :
command : client >1024 -> server 21
data : client >1024 -> server >1024

A quick summary of the pros and cons of active vs. passive FTP is also in order:

Active FTP is beneficial to the FTP server admin, but detrimental to the client side admin. The FTP server attempts to make connections to random high ports on the client, which would almost certainly be blocked by a firewall on the client side. Passive FTP is beneficial to the client, but detrimental to the FTP server admin. The client will make both connections to the server, but one of them will be to a random high port, which would almost certainly be blocked by a firewall on the server side.

Luckily, there is somewhat of a compromise. Since admins running FTP servers will need to make their servers accessible to the greatest number of clients, they will almost certainly need to support passive FTP. The exposure of high level ports on the server can be minimized by specifying a limited port range for the FTP server to use. Thus, everything except for this range of ports can be firewalled on the server side. While this doesn't eliminate all risk to the server, it decreases it tremendously.
__________________

Changeing ur IP address in 30 Sec.

2008-09-07T04:09:00.000-07:00

------------------------------------------START-----------------------------------------------------
@echo off
title NETWORK RESET SCRIPT
:prompt
color 1f
cls
echo NETWORK RESET SCRIPT
echo.
echo Type r to Reset Network
echo Type p to do a ping test
echo Type c to go to Command Prompt
echo Type q to exit
set /p answer=
if ‘%answer%’ == ‘r’ goto test
if ‘%answer%’ == ‘R’ goto test
if ‘%answer%’ == ‘C’ goto cmd
if ‘%answer%’ == ‘c’ goto cmd
if ‘%answer%’ == ‘q’ goto quit
if ‘%answer%’ == ‘Q’ goto quit
if ‘%answer%’ == ‘P’ goto ping
if ‘%answer%’ == ‘p’ goto ping
pause >nul

:test
cls
echo —————————————————-
echo - RELEASING IP…. -
echo —————————————————-
ipconfig /release >nul
echo.
echo Done!
echo.
echo —————————————————-
echo - RESETTING IP LOG… -
echo —————————————————-
@netsh int ip reset C:\Windows\TEMP\IPRESETLOG.txt >nul
echo.
echo Done!
echo.
echo —————————————————-
echo - FLUSHING ARP TABLES… -
echo —————————————————-
@arp -d >nul
echo.
echo Done!
echo.
echo —————————————————-
echo - FLUSHING DNS… -
echo —————————————————-
@ipconfig /flushdns >nul
echo.
echo Done!
echo.
echo —————————————————-
echo - RENEWING IP… -
echo —————————————————-
@ipconfig /renew >nul
echo.
echo Done!
echo.
cls
echo —————————————————-
echo Heres Your Status: -
echo —————————————————-
ipconfig /all
echo.
echo Press Any Key to Go To Menu
pause >nul
goto prompt

:ping
cls
echo —————————————————-
echo Starting Ping Test… -
echo —————————————————-
echo.
ping google.com
echo.
echo Press Any Key to goto MENU
pause >nul
goto prompt

:quit
cls
echo Thanks For Using The Network Reset Script
pause
exit

:cmd
@color 7
cls
cmd
@echo on
------------------------------------------------END-----------------------------------------

Copy paste this code in ur Notepad
"save as " .bat
Follow the instruction .
Enjoy

Windows Firewall

2008-09-07T03:58:00.000-07:00

Windows Firewall

What is Windows Firewall?

A firewall helps to keep your computer more secure. It restricts information that comes to your computer from other computers, giving you more control over the data on your computer and providing a line of defense against people or programs (including viruses and worms) that try to connect to your computer without invitation.

You can think of a firewall as a barrier that checks information (often called traffic) coming from the Internet or a network and then either turns it away or allows it to pass through to your computer, depending on your firewall settings.

See the following illustration:

In Microsoft Windows XP Service Pack 2 (SP2), Windows Firewall is turned on by default. (However, some computer manufacturers and network administrators might turn it off.) You do not have to use Windows Firewall—you can install and run any firewall that you choose. Evaluate the features of other firewalls and then decide which firewall best meets your needs. If you choose to install and run another firewall, turn off Windows Firewall.

How does it work?

When someone on the Internet or a network tries to connect to your computer, we call that attempt an "unsolicited request." When your computer gets an unsolicited request, Windows Firewall blocks the connection. If you run a program such as an instant messaging program or a multiplayer network game that needs to receive information from the Internet or a network, the firewall asks if you want to block or unblock (allow) the connection. If you choose to unblock the connection, Windows Firewall creates an exception so that the firewall won't bother you when that program needs to receive information in the future.

For example, if you are exchanging instant messages with someone who wants to send you a file (a photo, for example), Windows Firewall will ask you if you want to unblock the connection and allow the photo to reach your computer. Or, if you want to play a multiplayer network game with friends over the Internet, you can add the game as an exception so that the firewall will allow the game information to reach your computer.

Although you can turn off Windows Firewall for specific Internet and network connections, doing this increases the risk that the security of your computer might be compromised.

What Windows Firewall does and does not do?

It does: It does not:
Help block computer viruses and worms from reaching your computer. Detect or disable computer viruses and worms if they are already on your computer. For that reason, you should also install antivirus software and keep it updated to help prevent viruses, worms, and other security threats from damaging your computer or using your computer to spread viruses to others.
Ask for your permission to block or unblock certain connection requests. Stop you from opening e-mail with dangerous attachments. Don't open e-mail attachments from senders that you don't know. Even if you know and trust the source of the e-mail you should still be cautious. If someone you know sends you an e-mail attachment, look at the subject line carefully before opening it. If the subject line is gibberish or does not make any sense to you, check with the sender before opening it.
Create a record (a security log), if you want one, that records successful and unsuccessful attempts to connect to your computer. This can be useful as a troubleshooting tool. If you want Windows Firewall to create a security log, see Enable security logging options. Block spam or unsolicited e-mail from appearing in your inbox. However, some e-mail programs can help you do this. Check the documentation for your e-mail program to learn more.