[4183] in linux-net channel archive
Re: 2 NIC's in linux
daemon@ATHENA.MIT.EDU (cs95rro@brunel.ac.uk)
Sun Aug 25 06:05:44 1996
From: cs95rro@brunel.ac.uk
To: ajsaunders@duriron.com
Date: Sun, 25 Aug 1996 10:56:50 +0100 (BST)
Cc: Linux-net@vger.rutgers.edu
In-Reply-To: <199608232131.RAA01193@WHQ.duriron.com> from "Andrew J. Saunders" at Aug 23, 96 05:43:35 pm
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> I started out with a single NIC in the Linux that was connected to a
> Cisco 4500 router that was pointed to our ISP via frame relay.
Nice routers those. Cost a fortune sadly. Linux is cheaper. :-) (And does more)
> Things have worked fine. Our class C address was 206.110.16.X
> numbers changed to protect the innocent ;-)
>
> I have now installed a second card, and assigned it a reserved
> address of 172.16.120.3 for our internal network.
I can't be sure because I don't know the real numbers but are those 'reserved'
numbers 'reserved for local use'? If so, than you will need IP masquerading
enabled on the Linux machine. (And, AFAIK, ping never works over IP
masquerading anyway. Or was that traceroute?)
The reason you can't ping past the Linux box is that there is no routing
information on the Internet for your address - that's why it's reserved for
local use, so that people can set up a network connected to a network that's
connected to the internet without being on the internet and having to get
some IP addresses. You could make the Cisco respond to pings by changing it's
routing entries for your intranet to point to the Linux box as a router but
the rest of the internet would still not be able to talk to your intranet.
As I mentioned earlier, you need IP masquerading. There's a better explanation
in /usr/src/linux/Documentation/Configure.help, along with a pointer to a
FAQ.
And for the record, a second Cisco box would do exactly the same as Linux.
* cs95rro@brunel.ac.uk ryan@bcs.org.uk * Ryan Richard O'Connell 0958 204802 *
* http://www.brunel.ac.uk:8080/~cs95rro * Finger: cs95rro@molnir.brunel.ac.uk *
* Chances are we might be stars and live forever. *
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