How do masquerade and set up firewall on two network interfaces?

How do masquerade and set up firewall on two network interfaces?

Post by J. S. Jense » Fri, 24 Jul 1998 04:00:00

I have two network interfaces into our LAN.  On one interface, there are
no TCP/UDP port restrictions whatsoever.  However, on another interface,
I would like to limit the number of connecting ports to about 3 or 4.

I can set up a default policy for ipfwadm input rules to deny all or
accept all.  Will I then have to DISABLE ALL but those 3-4 ports on one
interface or ENABLE ALL ports on the other interface?

How do I do this on one machine?


J. S. Jensen


1. Question: two network cards, IP masquerading, Firewall, etc.


First of all please forgive me if this is an FAQ, but I'm not a
networking guru
who wants to set up small network.

We have about 10 PC's some of them running Linux and some of them
Windows. Those PC's are connected via AT&T WaveLAN wireless network
(which are supported by Linux BTW).  We have only one designated IP
So we want to make one of the PC's (running Linux with two network cards
one to internet and the other to other PC's) as the internet gateway for
the remaining
PC's.  (We also need to share a printer connected to Linux machine which
think can be handled later by samba). Anyway, the steps we think
necessary are

        1. Configuring Linux box with two network cards.
        2. IP masquerading
        3. Firewall setup (? necessary )

Problem is we don't know the details.

Could someone give me a step by step instructions to do this ?
What documents should I look for ?

Thanks in advance and it would be greatly appreciated if you
could send me an e-mail as well.

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