Philip, : Thanks. Can you give me more pointers about ToS based routing? any link? Short answer: The ToS bit on a packet can be used as a key for route selection. You should use "ip route add tos 0xc0 default via $GATEWAY_IP". Longer answer: Here's a primer on kernel routing selection. This documentation is targetted to network admins who do not know C, that is, people who cannot read kernel code. http://linux-ip.net/html/routing-selection.html I have not completed the section on ToS routing, although if you understand the general architecture, you will not need anything else. Be warned, there is not much here: http://linux-ip.net/html/adv-rpdb.html#adv-routing-tos If you are not familiar with "ip route", see the following for some examples: http://linux-ip.net/html/tools-ip-route.html and see the iproute2 manual (by Alexey Kuznetsov) for all of the accepted parameters to the "ip route" command. http://linux-ip.net/gl/ip-cref/ http://linux-ip.net/gl/ip-cref/node69.html I solicit opinions, feedback, and criticism of the above documentation (except for Alexey's manual). Good luck, -Martin -- Martin A. Brown --- SecurePipe, Inc. --- mabrown@securepipe.com - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html