[SOLVED] IP Route UDP and TCP packets different interfaces

howudodat · 09-13-2010, 05:06 PM

I have 2 hdlc interfaces in my box both using RF links. One of the links is uni-directional, the other bi-directional. I want to send all TCP traffic through the bi-directional link and UDP traffic through the uni link. I've got source routing working through the two interfaces

Code:

ip route add 10.10.1.0 via 192.168.1.2 dev hdlc0 tab 1
ip route add 10.10.1.0 via 192.168.1.2 dev hdlc1 tab 2

ip rule add from 10.10.2.101/32 tab 1 priority 500
ip rule add from 10.10.2.102/32 tab 2 priority 600

However I'd like to have a rule that looks more like this:

Code:

ip rule add PROTO udp tab 1 priority 500
ip rule add PROTO tcp tab 2 priority 600

How would I go about doing something like this?

Peter

hda7 · 09-14-2010, 07:51 AM

Quote:

Originally Posted by howudodat

I have 2 hdlc interfaces in my box both using RF links. One of the links is uni-directional, the other bi-directional. I want to send all TCP traffic through the bi-directional link and UDP traffic through the uni link. I've got source routing working through the two interfaces

Code:

ip route add 10.10.1.0 via 192.168.1.2 dev hdlc0 tab 1
ip route add 10.10.1.0 via 192.168.1.2 dev hdlc1 tab 2

ip rule add from 10.10.2.101/32 tab 1 priority 500
ip rule add from 10.10.2.102/32 tab 2 priority 600

However I'd like to have a rule that looks more like this:

Code:

ip rule add PROTO udp tab 1 priority 500
ip rule add PROTO tcp tab 2 priority 600

How would I go about doing something like this?

Peter

Take a look at iptables. It has a mechanism to match packets of specific protocols.

howudodat · 09-22-2010, 05:14 PM

So in order to give a more useful reply to others who might be searching for a response:
Source routing can be performed by iptables, using the mangle table and the POSTROUTING chain. Typical entries would look like:

Code:

iptables 
    -A POSTROUTING    Chain to add rule to
    -t mangle         Table to add rule to
    -j ROUTE          Action we want to take
    --gw 10.1.1.1     Gateway to send the packet to
    -p tcp            match protocol tcp
    --dport 27000     match dest port 27000

Peter