[Openswan Users] ICMP reply from wrong host

[Nicklas Bondesson]

Hello list,

Network A and network B are connected in a host-to-host setup using
openswan.

Network A [172.16.32.0/24] -- <INTERNET> -- Network B [192.168.0.0/24]

172.16.32.100 is the gateway for network A and 192.168.0.100 is the gateway
for network B.

When I ping the ipsec gateway on network A from a host on network B, I get
an ICMP reply from another host on that network (this host changes over
time, in this example it is .57 but I've seen others as well, including my
own workstation). The same thing is happening with traceroute.

Tracing route to 172.16.32.100 over a maximum of 30 hops

  1    <1 ms    <1 ms    <1 ms  192.168.0.1
  2    26 ms    25 ms    26 ms  172.16.32.57

I have no problem trying to communicate with any of the other hosts on
network A, just the gateway. I can however ping the ipsec gateway on network
B from network A (it responds with the correct ip).

I would be very glad if anyone care to shed some light or throw some
pointers.

Best Regards,
Nicklas