[LARTC] routing ssh to secondary uplink

[Torsten Luettgert]

On Do, 2006-07-06 at 09:49 +0300, devnull at plugthebox.net wrote:
> Hello,
> I'm following this HOWTO
> http://linux-ip.net/html/adv-multi-internet.html to route outgoing SSH
> from a secondary ISP. I can see using tcpdump,jnettop,iftop that when
> one of the computers located in my internal network is trying to SSH to
> a box online using SSH, packets are routed via the secondary internet
> ethernet card. However, packets don't seem to know how to get back.

I understand the two uplinks have different ethernet interfaces.
Did you disable rp_filter? Perhaps

echo 0 > /proc/sys/net/ipv4/conf/(interface for ssh)/rp_filter

would help. You can also use tcpdump on that interface to see if
the return packets arrive at your box, and on the inner interface
to see if they leave it.

Regards,
Torsten