Re:firewall question

From: K Smith (
Date: 11/08/01

Date: Wed, 07 Nov 2001 21:45:43 -0500
To: freebsd-security@FreeBSD.ORG
From: K Smith <>


I would suggest double checking each IP configuration (including subnet mask).
The next step is to use basic tools such as ping, traceroute and arp to
determine the behavior of your network. Utilize a traffic analyzer such as
tcpdump or ethereal and an ethernet hub (if you are using a switch) if you
haven't discovered the source of the problem using the previous steps. Your
problem could be complex, but will most likely be caused by a simple
configuration error.

BTW: You would probably get a better response posting this to a more general
Q&A list, as it doesn't particularly pertain to security.

Good Luck!

>I've been playing with setting up a firewall. This is the setup:
>The firewall PC is running FreeBSD 4.4 with the default 'simple' firewall
>running. There are two ethernet cards in it, one at IP talking
>to the outside network. The other ethernet card is using IP and is
>talking to an internel network of two PCs.
>One PC is running FreeBSD 4.4 and is at IP and the other PC is
>running Win98 and is at IP Both are using as the default
>If both machines are plugged into the network and running everything seems to
>be working fine. However as soon as I shut down the Win98 box or unplug it
>from the network, the FreeBSD machine can't communicate out of the firewall
>anymore. Plug the Win98 box back in and it starts working again.
>Any suggestions? TIA
>Tom Greenwalt (F.O.E.) Trancer Software Inc.
>9099 7th Street NE
>Minneapolis, MN 55434-1113
>---- When I'm good I'm very good, when I'm bad I'm better, ---->---------- But
when I'm evil you better run. -------------

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