[Haifux] IP Masquerading lecture uploaded to Google Video
eli at billauer.co.il
Mon May 5 20:20:57 MSD 2008
Almost exactly five years ago, I gave my IP Masquerading lecture, which
showed the fundamentals and hands-on of getting several computers to
share an ADSL/cable modem connection (plus a bit about firewalling).
The lecture was recorded on video at the time. I've recently uploaded a
slightly edited version of that lecture to Google video.
As far as I can see, it's hasn't lost any relevance since (except for
the ipchains part). The slides are in English, but I speak Hebrew on the
So if anyone is interested, it's at
The slides in PDF format:
Below: A copy of the original invitation to the lecture:
IP masquerading is a technique of manipulating IP packets, which makes
it possible for computers to "hide themselves" behind IP addresses that
they don't actually own. I suppose that the most popular application of
this is sharing an IP number between more than one computer.
Or in practice: Having a single ADSL (or cable) connection shared
between several, possibly non-Linux computers. It turns out to be quite
easy to get it working well. If you know what you're doing, that is.
The lecture will deal with how iptables works in general, and emphasize
the subject of masquerading (or NAT, to be accurate). The aim is to
understand the mechanism of iptables, and how IP packets are going
through it. Example commands for setting up both a firewall and IP
masquerading will be shown and discussed.
I will also discuss how to fake the address of your ISP's DNS, so you
can configure a static address on the local computers, even if the real
address isn't static.
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