Have a UNIX server. User wants to write programs to receive SNMPTraps. I *thought* I could redirect incomming traffic to port 162 to a high port, (like 4162) where the user could have his programs receive the messages with no special privelages? Anyway, a completely normal box, no special firewalling rules.... The only rule I create is: iptables -t nat -A POSTROUTING -p udp -m udp --dport 162 -j REDIRECT --to-ports 4162 Now, the user starts his program that binds to udp port 4162 ( I can see it with "netstat -nap" ) but he doesn't see any packets coming in. I run tcpdump -n | grep snmptrap and I see packets coming from the network to the server on udp port 162, and the server sending back icmp unreachable packets back to the sources?? Why doesn't the redirect work? -Ben.
