- Transparent Proxy and Redirection with LINUX 2.2
- User-Space Redirection--The Illusion of the Facade
- Transparent Proxy Support--Slight of Hand
- Kernel Port Forwarding--High Wizardry
This article is about methods to take traffic headed to one destination and point it toward a different destination, without the sender (and sometimes the receiver) being aware that any such activity is taking place. The action doesn't necessarily have to be covert; it may be the only way to allow access from the outside to systems inside a masquerading firewall. Redirection options run the gamut from simple user-space processes to kernel firewalling rules, a combination of these two, and then finally some more complex kernel rules that perform reverse masquerading. This article covers each of these with an example.