when i type the command:

# iptables -L

i get the following error:

modprobe: Can't locate module ip_tables
iptables v1.2.11: can't initialize iptables table `filter': iptables who? (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.

this would make sense to me if i knew there had to be a module in /lib/modules, but from what i can tell there shouldn't be. this has me stumped at the moment. maybe i'm not telling the OS something else it needs to know? the iptables executable is in /usr/local/sbin and i thought that is all i needed to get started with this. all i am trying to do is route between 2 NICs. any help would be appreciated. thanks.

hhmm...both come back saying can't locate the modules...i know i compiled and installed this stuff. i'll check again, but what else could it be? thanks.

I have just had the same problem on several Red Hat 9 machines.

I am an instructor teaching Linux networking to adult students. While preparing for a class, I used the following commands:

I have just had the same problem on several Red Hat 9 machines.

I am an instructor teaching Linux networking to adult students. While preparing for a class, I used the following commands:
- ifconfig to view and change IP addresses
- mii-tools
- ethtools
- route command to view and change the local routing table.

At some point I did an iptables -F to flush the rules. That is where the problem (as described) started. I didn't see any connection between my iptables problem and the networking commands that I used.

HOWEVER, today in class, on freshly imaged RH9 boxes, fully patched, doing the same networking commands produced the same problem.

What could be the connection between manually viewing and modifying network settings AND iptables blowing up???

The modules that iptables wants exist in the correct directories and ldconfig / ld.so etc know they are there. Reinstalling/ upgrading iptables did't help either.

Thanks,
Jim