On Aug 24, 2011, at 6:06 AM, Brian Raaen wrote: > The only issue with this is that the Linux box is not acting as a router, but > as the egress devices. I'm trying to figure out how to properly get my > application to 'color' the traffic. standard BSD sockets appear to have no > concept of 'Labels'. Still seeing what I can do to match the traffic. I am > probably going to see if I can work out a hack with the development team to > use DSCP values to tag the traffic and then act accordingly on the ingress > router. I appreciate all the ideas presented so far. >
You can classify this in the OUTPUT or POSTROUTING table with ipchains. Take a look at the man page for it. There's lots of information online about how to do this. I recall a sysadmin who I worked with 15 years ago that thought of routers as the black boxes that got their packets around, but a little bit of understanding of these lower levels of the kernel/networks will go a long way. Some help: INPUT (for packets destined to local sockets) FORWARD (for packets being routed through the box) OUTPUT (for locally-generated packets; for altering locally-generated packets before routing) PREROUTING (for altering packets as soon as they come in) POSTROUTING (for altering packets as they are about to go out) http://linux-ip.net/html/adv-multi-internet.html should also prove useful in your research. You likely are going to end up using the localhost fwmark/mark. Some tools show this number in hex, others decimal, so keep this in mind during your debug process. - Jared
