I am having a problem trying to setup a QNX system for NAT using IP Filter.
I am using the QNX port of IP Filter version 3.4.6 under Neutrino 6.1.

I’d like to redirect two ports (telnet and ftp) from the NAT box to their
respective actual ports on my private node. The ipnat.rules file looks

map en0 → 0/32
rdr en0 port 12000 → port 21 #ftp
rdr en0 port 15000 → port 23 #telnet is my private node’s IP and is the interface to the
public network.

When I run ipnat on the above rule file, ipnat will read in all three
entires but the third line (second rdr rule) is not listed as active. By
typing “ipnat -l”, I only see the first two lines. If I modify the second
rdr rule and change its en0 to en1 or its IP from to something
else then this rule is accepted and listed as active.

I have seen many examples on the web where you can redirect multiple ports
from one interface to another like how I intend to do. This makes me wonder
if I am doing something wrong or is there a bug in the IP Filter port that I
am using. Would appreciate if someone can shed some light onto this.


  • Murtaza