This is the first time I ever see this kind of problem... maybe it's because I have such a weird configuration right now. I'm testing a host with two internet connections. the default route is only one of the two connections. The other link is not involved at all. However, I set a rule in OUTPUT mangle that will mark icmp traffic and then I have an ip rule that forces it to use a routing table that is configured to use the "unused link". I thought that it meant that icmp would come out from that interface.. and as I am masquerading traffic through that interface, the src address would be set to that interface's address. It's a BIG surprise to see that it's not happening. I tcpdumped traffic and noticed that traffic is coming through the unused interface... but still has the src address of the other interface. Is that normal? And how can I make it to use the "correct" address?
