Re: ip masquerading in 2.1.x

John Corey (
Fri, 16 Jan 1998 20:54:46 -0600

> Ok, the only thing different from 2.0.x is that you need to enable ip
> forwarding now to get it to work.. I'll show you what I put in my rc.local
> script.
> # Load IP Masquerading modules
> modprobe ip_masq_ftp
> modprobe ip_masq_irc ports=6665,6666,6667,6668,6669,31337
> modprobe ip_masq_raudio
> modprobe ip_masq_quake
> modprobe ip_masq_vdolive
> # Enable IP Masquerading forwarding rules
> ipfwadm -F -p masquerade
> ipfwadm -F -a m -S -D -W eth0
> # Start IP forwarding
> echo "1" > /proc/sys/net/ipv4/ip_forwarding
> Now, I can't be sure that having masquerade as the default rule for
> forwarding is a smart thing to do, but that's the only way I could get it
> to work. If I use default rule deny, it will not work.
> Regards,
> Dave.

On my system, when I put echo 1 > /proc/sys/net/ipv4/ip_forwarding (only
differnce from above is the lack of "s), it didn't get done. It was the
last line in rc.local. After logging in, reading that
/proc/.../ip_forwarding gave back 2. Instead I had to result to just
doing it in ip-up instead.