I've been doing the Linux Gazette Answer Guy column for almost three years now. Normally I insert links directly to any resources to which I refer in my answers. However, sometimes I find it difficult to reach a particular document or web site. In those cases, licenses and copyrights permitting, I'll post copies of those documents here and embed the additional links as appropriate.
Here's a document on the Linux kernel's support for Policy based routing MICRO-HOWTO by Horacio J. Peņa, email@example.com I should probably do some research and write up an update to it. We'll see if I can find the time for that.