[Openswan Users] Port 1 - solution

[Stephen J. McCracken]

This is just to get this in the archives as it is solved. (It's a NAT
problem.)

I was having trouble with ports being rewritten to port 1.  Example:

BoxA --- GwA ====== GwB --- BoxB

GwA running OpenSWAN (openswan-2.1.5-2 Fedora RPM) and GwB a Multitech
RoutFinder 550 (MT550VPN).

I would try to ssh from BoxA to BoxB and get this:

15:22:35.859664 IP BoxA.38537 > BoxB.22: S 51958428:51958428(0) win 5840
<mss 1460,sackOK,timestamp 257583923 0,nop,wscale 2>
15:22:35.863491 IP BoxB.22 > BoxA.38537: S 3558425983:3558425983(0) ack
51958429 win 5792 <mss 1336,sackOK,timestamp 12106235
257583923,nop,wscale 2>
15:22:35.863555 IP BoxA.38537 > BoxB.22: . ack 1 win 1460
<nop,nop,timestamp 257583927 12106235>
15:22:35.890997 IP BoxB.1 > BoxA.38537: P 3558425984:3558426007(23) ack
51958429 win 1448 <nop,nop,timestamp 12106262 257583927>
15:22:36.093361 IP BoxB.1 > BoxA.38537: P 0:23(23) ack 1 win 1448
<nop,nop,timestamp 12106465 257583927>
15:22:36.499231 IP BoxB.1 > BoxA.38537: P 0:23(23) ack 1 win 1448
<nop,nop,timestamp 12106871 257583927>

I noticed others were having similar problems:

http://lists.virus.org/users-openswan-0502/msg00239.html

And found the answer through this post:

http://lists.virus.org/users-openswan-0407/msg00002.html

That references this post:

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=215980

I had to add in the following to solve the port 1 problem:
iptables -A POSTROUTING 1 -p esp -j ACCEPT -t nat