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Sunday, August 15, 2010

Subnet Masks and Subnetting

Subnetting in Practice
Subnetting works by applying the concept of extended network addresses to individual computer (and other network device) addresses.

An extended network address includes both a network address and additional bits that represent the subnet number.
... . Together, these two data elements support a two-level addressing scheme recognized by standard implementations of IP. The network address and subnet number, when combined with the host address, therefore support a three-level scheme.

Consider the following real-world example. A small business plans to use the 192.168.1.0 network for its internal (intranet) hosts. The human resources department wants their computers to be on a restricted part of this network because they store payroll information and other sensitive employee data. But because this is a Class C network, the default subnet mask of 255.255.255.0 allows all computers on the network to be peers (to send messages directly to each other) by default.

The first four bits of 192.168.1.0 -
1100
place this network in the Class C range and also fix the length of the network address at 24 bits. To subnet this network, more than 24 bits must be set to '1' on the left side of the subnet mask. For instance, the 25-bit mask 255.255.255.128 creates a two-subnet network as follows. Network address
(24 bits) Subnet number
(1 bit) Extended network Host address range
11000000 10101000 00000001 0 192.168.1.0 192.168.1.1 - 192.168.1.127
11000000 10101000 00000001 1 192.168.1.128 192.168.1.129 - 192.168.1.255


For every additional bit set to '1' in the mask, another bit becomes available in the subnet number to index additional subnets. A two-bit subnet number can support up to four subnets, a three-bit number supports up to eight subnets, and so on.
Private Networks and Subnets
As mentioned earlier in this tutorial, the governing bodies that administer Internet Protocol have reserved certain networks for internal uses. In general, intranets utilizing these networks gain more control over managing their IP configuration and Internet access. The default subnet masks associated with these private networks are listed below. Network address range Default mask
10.0.0.0 - 10.255.255.255 255.0.0.0
172.16.0.0 - 172.31.255.255 255.240.0.0
192.168.0.0 - 192.168.255.255 255.255.0.0


Consult RFC 1918 for more details about these special networks.
Subnetting Review

Subnetting allows network administrators some flexibility in defining relationships among network hosts. Hosts on different subnets can only "talk" to each other through specialized network gateway devices like routers. The ability to filter traffic between subnets can make more bandwidth available to applications and can limit access in desirable ways.

Can Someone Find me with my IP Address?

Possibly, but most likely not without a subpoena.

In most cases all that can be easily determined is who the person's ISP is and possibly the state and city they reside in.

In some cases with static IP address DSL or business DSL services the ISP provides IP allocation records to the American Registry for Internet Numbers (http://www.arin.net), the non-profit organization responsible for managing Internet numbering resources in North America.

As an example SBC used to include customer information in those allocation records, but due to privacy concerns now uses their own information with a customer reference number.

For users who want to afford themselves some additional level of anonymity we suggest you read about internet anonymity, Proxy Servers, and how to hide your ip address.

Try using this tool to look up your IP address.
How can someone find out who I am?

A little background first.

IP address allocation is handled by The Internet Assigned Numbers Authority (IANA). IANA in turn, delegate authority to Regional Internet Registries (RIRs). The RIRs, in turn, following their own regional policies, further delegate blocks of IP addresses to their customers, which include Internet Service Providers (ISPs) and end-user organizations.

Each of the RIRs handles a specific geographic area:
ARIN (North America and portions of the Caribbean)
AfriNIC (Africa)
APNIC (Asia and the Pacific region)
LACNIC (Latin America and portions of the Caribbean)
RIPE (Europe, Middle East, Central Asia)

Each of these organizations allow lookups to be to that data. Different ISP's segment their blocks of IP addresses by region and you can see that in the lookup. The lookup provides the name and address of the organization the block of IP addresses was allocated to. The ISP's can name these blocks if they choose. The naming often indicates a geographic location, for example, IRV-CA, aka Irvine, California.

Here are links to the URLs where you can lookup an IP address. Be aware that if you lookup an Asian allocated IP address in a different region's RIR it will provide a link to the appropriate RIR.
North America and portions of the Caribbean
Africa
Asia and the Pacific region
Latin America and portions of the Caribbean
Europe, Middle East, and Central Asia

In general, I start by looking up an IP address with ARIN seeing what geographic location information I can learn from the results.

From there I do a reverse DNS (rDNS) lookup to see what hostname the ISP provides. A hostname is something like www.example.com, or can be more specific to include regional information.

From there I do a traceroute which displays the hostnames many of the machines in between two points on the internet. (I'm making this *really* none technical here...) Sometimes the rDNS/hostname of a specific IP address will not reveal any location but the rDNS/hostname of the machine next along the path will reveal some.

That's about all the information that can be obtained without a subpoena. In many cases people reveal small amounts of personal information about themselves on forums, chat rooms, blogs, etc that can be used to build a profile of who you might be.

How do I use a Proxy Server?

Please be aware that the use of proxy servers without the express permission from the owner of the proxy server may be illegal in some states and/or countries. Use at your own risk.

Use your favorite search engine and search for 'proxy server list'. You'll find many sites with lists of proxy servers, their IP address, the port they listen on, and usually what country they are in. Write down a few of them.


Proxy Types

You may see references to four different types of proxy servers:
Transparent Proxy

This type of proxy server identifies itself as a proxy server and also makes the original IP address available through the http headers. These are generally used for their ability to cache websites and do not effectively provide any anonymity to those who use them. However, the use of a transparent proxy will get you around simple IP bans. They are transparent in the terms that your IP address is exposed, not transparent in the terms that you do not know that you are using it (your system is not specifically configured to use it.)
Anonymous Proxy

This type of proxy server indentifies itself as a proxy server, but does not make the original IP address available. This type of proxy server is detectable, but provides reasonable anonymity for most users.
Distorting Proxy

This type of proxy server identifies itself as a proxy server, but make an incorrect original IP address available through the http headers.
High Anonymity Proxy

This type of proxy server does not identify itself as a proxy server and does not make available the original IP address.

Please make sure to read about anonymous proxy risks before using a proxy server.

If you need further assistance using proxy servers please post a question in the proxy server forum.
Browser Settings

The following are instructions to configure various browsers to use an http proxy server.
Instructions for Internet Explorer 6.0
On the Tools menu in Internet Explorer, click Internet Options, click the Connections tab, and then click LAN Settings.
Under Proxy server, click to select the Use a proxy server for your LAN check box.
In the Address box, type the IP address of the proxy server.
In the Port box, type the port number that is used by the proxy server for client connections (by default, 8080).
You can click to select the Bypass proxy server for local addresses check box if you do not want the proxy server computer to be used when you connect to a computer on the local network (this may speed up performance).
Click OK to close the LAN Settings dialog box.
Click OK again to close the Internet Options dialog box.
Instructions for Internet Explorer 5
Click Start, point to Settings, click Control Panel, and then double-click Internet.
Click the Connections tab, click LAN Settings, and then click to select the Use Proxy Server check box.
In the Address box, type the appropriate proxy server information, and use the following format: http://

Click Advanced, and then type the appropriate proxy settings in the Servers area. Use the following syntax for the proxy settings: http://
: where
is the Web address of the proxy server, and is the port number that is assigned to the proxy server. For example, if the proxy server's address is "proxy.example.microsoft.com" and the port number is 80, the setting in the Proxy Server box should appear like this: http://proxy.example.microsoft.com:80 Important: If you use a backslash (\) instead of a slash (/) in the proxy server's address, the settings disappear from the Proxy Server box and Internet Explorer does not find the proxy server.
Instructions for Firefox 3.0
Select the Tools Menu
Select Options
Select the Advanced Icon
Select the Network tab
Under connection select Settings
Under Settings you can chose "Auto-Detect Proxy setting for this network" or "Manual Proxy Configuration"
If choosing "Manual Proxy Configuration" Enter the IP address for the HTTP proxy server
Enter the port of the HTTP proxy server
Click Okay
Instructions for FireFox 2
Select the Tools Menu
Select Options
Select Connection Settings
Select Manual Proxy Configuration
Check Use the same proxy for all protocols
Enter the IP address for the HTTP proxy server
Enter the port of the HTTP proxy server
Click Okay
Instructions for Netscape 8.1
Select the Tools Menu
Select Options
Select General
Select Connection Settings...
Check Manual Proxy Configuration
Enter the proxy server's IP address in the HTTP Proxy field and the proxy's port into the Port field.
OK your way out
Instructions for Netscape 7.1
Select the Edit Menu
Select Preferences
Maximize Advanced
Select Proxies
Choose Manual proxy configuration
Enter the proxy server's IP address in the HTTP Proxy field and the proxy's port into the corresponding Port field.
OK your way out
Opera 8.5
Select the Tools Menu
Select Preferences
Select Advanced Tab
Select Proxy Servers
Check the box next to HTTP
Enter the proxy server's IP address in the first box and the proxy's port in the box after "Port"
OK your way out
Safari 2.0.3
Select Preferences
Select Advanced
Select Proxies: Change Settings
Check the box next to Web Proxy (HTTP)
Enter the proxy server's IP address in the first box and the proxy's port in the box after the ":"
Select Apply Now

GhostSurf Review

GhostSurf is a computer software program that allows for anonymous surfing of the Internet. Like other software programs of this nature, Ghostsurf provides security for the private browsing of Internet websites. It also provides peace of mind. With Ghostsurf you get ideal Internet anonymity, which means that you have the ability to surf the web without be tracked or traced.
Why Surf Anonymously

There are a number of reasons why Internet users prefer to anonymously surf the web. One of the most important reasons is the level of vulnerability presented by Internet use. When visiting a website, you are revealing yourself (and data about your usage) to the targeting and data collection of many different agencies - federal authorities, search engines, and online marketing groups are just a few. Information regarding your computer system, browser, usage, and web history are all examples of what data targeting groups can collect.

Besides protecting personal information, there are many logical reasons for wanting to surf the web anonymously. Citizens of those countries with restrictive Internet or communication policies will want to mask their particular web use and habits. Similarly, those who view the Internet at work may want to hide data from their employer on what websites have been visited exactly; for example, when looking for a new job.
How Ghostsurf Works

The idea of anonymous surfing is actually very simply: a buffer is placed in between your computer and the sites you view online. This buffer allows you to view the website, but doesn't allow the site (or anyone else) to trace your computer information back through that buffer. Most anonymous surfing software follows this pattern, and the buffer is generally a proxy server. When accessing the Internet under normal conditions, your computer's web browser will access and "talk to" the websites you want to view: this is how your computer is identified. However, when utilizing proxy-style anonymous surfing software, the proxy server becomes the middleman, the buffer. When accessing the Internet the computer's browser will first talk to the proxy server and then the proxy server will "talk to" the web site you want to view. As a result, the web site ultimately does not identify your computer's information; it identifies the proxy server.

Ghostsurf does not operate by this common, proxy-style, buffer method. The software instead offers a basic, but effective, method for anonymous surfing: scrambling your IP address. Whenever your computer connects to the Internet, Ghostsurf scrambles the IP address much like a good firewall package would do. This scrambling of the IP address encrypts your Internet connection, and provides you with the privacy and protection you need to surf anonymously.
The Benefits of Ghostsurf

One of the most attractive incentives of Ghostsurf is its level of personal customization. Privacy levels can be customized in real time to suit your changing needs, including the ability to block your personal information and mask your IP address. These privacy levels can be simply adjusted at any time by a moving slider. At one end is the lowest level, Normal, your computer data is sent through the Internet without modification, encryption, or rerouting. At the other end, the highest level, all personal information is removed, encrypted or rerouted. Again, the level of privacy customization is always up to you.

Beyond the moving slider of privacy protection, Ghostsurf allows users to exclude certain websites altogether. This means that some websites will be allowed your personal information if you choose so. For example, you may want your personal information blocked from Internet websites in general, but not your online banking website or web-based email. If so, Ghostsurf will allow you to customize your privacy levels in order to provide your personal information to these selected sites while still protecting you from all others.

And finally, Ghostsurf offers a number of useful program utilities that give you an added benefit. The software program will remove your browser history, delete any cookies and, if you have the Platinum edition, will remove pop-up ads. Ghostsurf also prevents adware and spyware with its own company-designed anti-spyware program, SpyCatcher. The software will also provide you with feedback regarding these utilities, such as the number of blocked cookies and pop-up ads, and blocked in-page ads. The software will also provide feed back on sent invisible requests via the Internet and sent secure requests as well.
The Drawbacks of Ghostsurf

Ghostsurf is an ideal software program that not only allows for anonymous surfing, but protects your computer as well. However, it does not offer a few items that anonymous surfers prefer. Ghostsurf lacks built-in anti-virus protection or spam tools. And for all of its additionally privacy protection and feedback tools, it does not offer reporting tools or any sort of log generation regarding the protection measures. Yet this is not surprising if considering how affordable the software really is. In this sense, it is an overall affordable program for anonymous surfing.

Anonymizer Anonymous Surfing Review

Anonymizer Anonymous Surfing is a computer software program that provides a method for privately browsing internet websites. Simply put, it means that you are able to use the Internet without being identified; or, in other words, it allows you to maintain internet anonymity. Internet anonymity means that you are not giving anyone the opportunity to trace or link your web activity, or personal information, back to you. Anonymizer Anonymous Surfing gives web users a sense of comfort. This is because Anonymous Surfing offers two distinct methods of privacy protection: 1) protection from the web site you are browsing, and 2) protection from someone watching or piggybacking your network connection.
Why Surf Anonymously

There are a number of reasons why Internet users prefer to anonymously surf the web. Most people do not understand how vulnerable using the Internet can be. Every time you visit a website, you are exposed to targeting and data collection by a number of agencies: federal authorities, search engines, online marketing groups. You may be watched, or your movements can be tracked throughout the internet. Web savvy persons and online advertisers can identify your operating system and determine what internet browser you use. They can uncover what websites you have visited, inspect your web history, and identify your IP address (which gives them your location as well as other personal computer information).
How the Software Works

Anonymizer Anonymous Surfing works by virtue of a proxy server established between the user and the web site intended for use. Under normal conditions (without the software), when a website is accessed by a user's computer, that computer is identified by the website. The process is a sort of dialogue between the two: it represents a "request to access the site" by your computer's web browser and a "granting of permission to use" by the website's server. Part of this initial request, then, is that the computer be identified as the user-agent.

This dialogue changes, however, when Anonymous Surfing's own proxy-style service is used to surf the website. It is the proxy server that requests to access the site, not your computer. Your computer's web browser will talk to the proxy server first, but it is the proxy server that then talks to the web site you want to view. As a result, the web site does not identify your computer as the user-agent; it instead identifies the anonymous proxy server.
The Good

Anonymizer Anonymous Surfing is extremely user friendly. The software can be enabled at the click of a button and instantly hides your IP address without having to modify any default settings. It works with all Internet browsers, even protecting the data you send over wireless networks, automatically. By routing your internet traffic through the Anonymizer proxy servers, Anonymous Surfing protects your computer against Host file and DNS cache poisoning. The software similarly protects your computer from phishing websites by notification when you attempt to visit one. It also protects you from spyware websites as well. The software's Digital Shredder Lite program will clean your browser history and cache files as well. All of this protection is packaged together with the Anonymous Surfing software in conjunction with a relatively low-cost yearly subscription service.
The Bad

Anonymizer Anonymous Surfing does have a few downfalls. The software's Digital Shredder Lite program that cleans your browser history and cache files can not handle international file names. It assumes that all file names should have roman characters. Therefore, the program is ineffective for multi-lingual applications. Fortunately the software's subscription service includes free customer support. However, even this has had its problems. Many customers have complained that it takes several attempts to reach a live person for assistance. And on some reported occasions, a customer service request email has been returned as "undeliverable".

How do I hide my IP address?

The most common method to hide your IP address is to use a proxy server in one form or another. A proxy server is a computer that offers a computer network service to allow clients to make indirect network connections to other network services. A client connects to the proxy server and then requests a connection, file, or other resource available on a different server. The proxy provides the resource either by connecting to the specified server or by serving it from a cache. In some cases, the proxy may alter the client's request or the server's response for various purposes.

There are several implementations of proxy servers that you can use to hide your IP address (in an attempt to remain anonymous on the internet):
Website Based Proxy Servers

A Website based proxy server is a website that provides a form for you to enter the URL of a website that you wish to anonymously visit. When you submit the form the website proxy server makes a request for the page that you want to visit. The machine usually does not identify itself as a proxy server and does not pass along your IP address in the request for the page. The features of these sites vary (ad blocking, javascript blocking, etc) as does their price. Some are free and some charge. Examples of website proxy services are:
Proxify.com
Browser Configured Proxy Servers

There are also stand alone proxy servers that allow for you to configure your browser to route your browser traffic through that machine, which then makes a request for a page on your behalf, and then sends you the results. These are usually used at no cost to the user. Since they are accessible to the public these are often quite slow. Please see instructions for using a proxy server.

There are a variety of types of these proxy servers:
Transparent Proxy
This type of proxy server identifies itself as a proxy server and also makes the original IP address available through the http headers. These are generally used for their ability to cache websites and do not effectively provide any anonymity to those who use them. However, the use of a transparent proxy will get you around simple IP bans. They are transparent in the terms that your IP address is exposed, not transparent in the terms that you do not know that you are using it (your system is not specifically configured to use it.) This type of proxy server does not hide your IP address.
Anonymous Proxy
This type of proxy server identifies itself as a proxy server, but does not make the original IP address available. This type of proxy server is detectable, but provides reasonable anonymity for most users. This type of proxy server will hide your IP address.
Distorting Proxy
This type of proxy server identifies itself as a proxy server, but make an incorrect original IP address available through the http headers. This type of proxy server will hide your IP address.
High Anonymity Proxy
This type of proxy server does not identify itself as a proxy server and does not make available the original IP address. This type of proxy server will hide your IP address.
Installed Software Proxy Servers

There are a variety of companies and software packages available at either a onetime cost or at an annual subscription. These are usually faster and more reliable than the above proxy servers. Some of these services would include:

How do I change my IP address?

"How do I change my IP address?" and "Can I change my IP address?" are probably the most commonly asked questions. Please attempt the following then, if that does not work, visit the Change IP Address forum.

Before trying any other methods to change your IP address, try turning off (or unplugging the power of) your Cable/DSL modem for five minutes. In many cases this will change your IP address. However, if that does not change your IP address, repeat the process for 8 hours (overnight works well) instead of 5 minutes. Hopefully this will result in an IP change.

If the above does not result in your IP address changing, please look through the below for the situation that best matches yours and attempt to change your IP address that way. Unfortunately you are not able to get your IP address to change in all cases, as it is ultimately determined by your ISP's DHCP configuration (when you've got a dynamically assigned IP address, that is.)
Windows
- Computer connected directly to the modem
Get to a command prompt. (START, run, cmd).


Type "ipconfig /release" (without the quotes, on the command line by itself).
Type "ipconfig /renew" (without the quotes, on the command line by itself).
Windows (second option)
- Computer connected directly to the modem
Get to a command prompt. (START, run, cmd).
Type "ipconfig /release" (without the quotes).
Shut down computer.
Turn off computer.
Turn off all ethernet hubs/switches.
Turn off cable/DSL modem.
Leave off overnight.
Turn everything back on.
Network with Router
Log into the router's admin console. (Often http://192.168.1.1/)
Release the IP address. (Method varies by router manufacturer)
Turn off router, ethernet hubs/switches, and the cable/DSL modem.
Leave off overnight.
Turn everything back on.

If you are using a cable/DSL modem and a router, you may wish to connect your computer directly to the cable/DSL modem. Please note that this could significantly impact your system security. This allows your ISP's DHCP to issue you a new (hopefully changed) IP address based of the (hardware) MAC address of your computer's ethernet card.

If all the above has not worked to change your IP address and you have a router, check and see if there is a "Clone MAC Address" option. Using it should change your IP address; however, you'll only be able to do it once (in most cases).

These will not work in all cases. If all else fails contact your internet service provider (ISP) and ask them if they are able to change your IP address or how long your connection needs to be off for your IP address to change.

If you trying to change your IP address because you are just trying to access web based forums you may wish to attempt to configure your internet browser to use a proxy server.
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