Joseph,
comments inline:
>I knew that I had to install a firewall and wanted to use a Linux box
>running ipfwadm. Once I installed Redhat 5.2, I then installed ipfwadm.
>There are two network cards in the computer. Network card 1 is plugged
>into the "firewall" hub. This is a 4 port 3-Com hub that only the T-1
>and the firewall is connected to. The second network card is plugged
>into the internal network.
>
>When I do this, the "firewall" hub has no lights for the firewall. But
>if I connect to the internal network everything is fine.
Ok, let's be incremental in our troubleshooting. I usually start at layer
1 and work my way up. This means verifying physical cabling, hubs and NIC
cards. Since you've stated that the hub has no light for the interface
you've plugged you Linux box into, there are 2 possibilities:
1) The light is burned out, giving a false reading
2) The reading is correct, meaning you've got no electrical signal on that
port
If it's #2, you've already found the problem. Nothing will work if you
don't have a physical signal. I would try the following:
1) try a different port on the hub
2) try plugging a known good station into the hub
3) try using a known good cable from the Linux box to the hub
4) try plugging the Linux boxes interface into a known good hub
One of these steps is sure to turn up where the problem is. Once you've
got a link light, test layer 3 connectivity by pinging from the Linux
interface to the router that I assume is terminating the T1 line. Then
ping the inside devices. Then ping from the inside to the router. Then
ping from the inside to the Internet.
Do this before installing any filtering on the Linux box. Once you've got
this far you can install the filtering and any future problems you can
attribute to incorrect filters.
HTH,
Kent
Kent Hundley
[EMAIL PROTECTED]
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