Port based routing

[epicqe]

Hi there,

What am I doing wrong??
Im trying to route traffic based on dst port.
I have a server with 4 interfaces and I need to route traffic which comes through bond3 to port 8888 that it will go back to same bond and to some specific GW.
Now it is coming through bond3 and reply goes through bond1 to default GW.

I was trying like this:

iptables -A PREROUTING -t mangle -i bond3 -p tcp --dport 8888 -j MARK --set-mark 1

ip rule add from all fwmark 1 table 11

ip route add default via x.x.x.x table 11

can you help?

BR, Nejc

[secondmouse]

LiNUX Horizon - Linux Advanced Routing mini HOWTO
second example

Add option dev bonX after via x.x.x.x in your ip route add default line to see if it makes a difference.

Good luck.

[daviest11]

Hopefully I can save someone else the weeks of pain I had, with this not working for no apparent reason!

Still doesn’t work? Check these things below:

rp_filter has to be set to 0 for given interfaces – 0 is the default value set by the Linux kernel, but some distributions (i.e. Ubuntu, Mandriva) alter it and set it to 1; just adding that to /etc/sysctl.conf should do the trick to make sure this value is set to 0 after reboot:

net.ipv4.conf.default.rp_filter=0
net.ipv4.conf.all.rp_filter=0

If you’re not rebooting any time soon, see what these value currently are with:

find /proc/sys/net -name rp_filter | xargs cat