Re: tlug: It works!

[jwb@example.com (Jim Breen)]

On Oct 9, 12:35pm, Darren Cook wrote:
} Subject: Re: tlug: It works!
>> >Why don't you set up IP Masquerading, ....
[snip]
>> >Of course, you'll need 2 network cards in the machine doing this.  Set the
>> >IP address of eth1 to 192.168.1.1, and then your other machines to
>> >192.168.1.2, .3, .4, etc, and have them use 192.168.1.1 as the default
>> >gateway.
>> 
>> Am I right in thinking those extra machines (eg. 192.168.1.2) can't do web
>> browsing, ftp, connect to a POP server, etc? So the only external machine
>> that can see them is the one with the two network cards?

I use IP masquerading at home, via the WinGate program, which is a Win95
app, but I understand there is a Linux equivalent. I can browse, telnet,
ftp, etc. from the other machines on the ethernet at home. (I use wingate
so that other family members can do MS-unspeakable-things while I am
Linuxing in the next room.)

>> What I'm thinking is that when a web server on the net gets a request from
>> 192.168.1.2 how will it know where to send the reply to? Or am I
>> misunderstanding something (again :-)?

How it works (with Wingate) is that the Wingate program acts as a proxy.
If I am on my notebook in the next room (192.168.1.2), I set 192.168.1.1
as the proxy in Netscape. All my http requests go off to port 80 on 192.168.1.1
which relays them up the PPP connection to the destination server. Thus,
as with any proxy operation, it looks as though the proxy is the client.

Similarly with Telnet. I make a telnet connection to 192.168.1.1, it
gives me back a prompt, and I give the address of the real target
machine. Effectively it runs two back-to-back TCP connections and passes
segments between them. Some people call it port-swapping, because at the
TCP header level, that is how it works.

HTH

Jim

-- 
Jim Breen        School of Computer Science & Software Engineering
Email: j.breen@example.com                Monash University
http://www.csse.monash.edu.au/~jwb/     Clayton VIC 3168 Australia
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