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Hey. I'm running cent 5.5 64-bit, 1 nic, eth0. I enabled ipv4 forwarding via:

echo '1' > /proc/sys/net/ipv4/ip_forward

and the machine locks up. cant switch ttys cant ssh into it. Had to hard reboot. Any ideas? I did this on a similar box a week ago with no problems. Id rather not take this machine down again needlessly, so, any ideas?

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why whould you need forwarding if you only have one nic? anyway, this shouldn't crash the machine, looks like you hit a hidden bug somewhere (probably triggered by your local configurations). any kernel stack traces? also try to log the full packet flow via iptables and see what's going on (deadloops? you said "can't access local ttys" and I assumed this is caused by some high cpu usage )

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