The Linux IP Personality patch adds to your Linux 2.4 kernel the
ability to have different 'personalities' network wise, that is to
change some characteristics of its network traffic, depending on
different parameters (anything you can specify in an iptables rule:
src/dst IP address, TCP or UDP port, etc.)
The characteristics that can be changed are:
- TCP Initial Sequence Number (ISN)
- TCP initial window size
- TCP options (their types, values and order in the packet)
- IP ID numbers
- answers to some pathological TCP packets
- answers to some UDP packets
They are deeply configurable.
This patch relies on the wonderful framework created by Rusty
Russel: netfilter.
More precisely, the patch adds a new iptables target (in a
kernel module) that can be used in the mangle table with a (patched)
iptables. This target is very configurable. See the documentation
section for more details on how it works.