About Linux IP Masquerade

What is IP Masquerade for Linux?

IP Masquerade is a networking feature in Linux. If a Linux host is connected to the Internet with IP Masquerade enabled, then computers connecting to it (usually on the same LAN, but can also be connected with other links such as modems or PLIP) can reach the Internet as well, even though they have no officially assigned IP addresses.

Why do I want to use it?

Think about a few people surfing the Internet simultaneously with a single modem connection, only paying for a single phone bill and Internet service charge at the end of the month... Pretty tempting, huh?!

A fellow user Jim also brought up a very good point: "For me the most compelling arguement was competing with my wife for 1 phone line to access the internet. With a Linux gateway with masquerading, we could share (no more arguements about who was connected) the line.", hence reducing the divorce rate. :-)

Well, I only have a 56kbps connection. Is the bandwidth enough for sharing?

It depends on what you're going to do. If a few users oftenly download files at the same time, then you should expect prolonged waiting time. However, if the users are only surfing the web and doing telnet, then it should be enough. As an example, my friend's 56kbps connection works reasonably well with 3 people surfing the web and one doing telnet. IP masquerade can also be useful on a larger user base when it is dedicated for retrieving emails from, let say, a popmail server.

Keep in mind that the Internet connection is not limited to a modem line, you can use an ISDN line, DSL, cable modem, satellite link, or even T1/E1 if available.

Is it reliable?

IP Masquerade had been out for several years and is maturing as Linux heads into the 2.2.x stage. Kernels since 1.3.x had built-in support already. Although some users reported minor problems with it, and not everything is working thru IP Masquerade yet, many people are using it rather satisfied, including businesses with considerably more traffic. So why not give it a try?

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