vpn tunnel interface

[Database Administrator]

Hey everyone,

I've got a Hamachi network with three machines:
A - FreeBSD 7.0 on LAN
B - Windows XP on LAN
C - Windows XP on WAN

Specifically, I am trying to connect from machine A to C. This works
perfectly between B and C, as well as B and A. When I try to ping C
from A, I get no response. Running tcpdump shows the outgoing packets
but none incoming. I am certain machine A machine is not blocking
traffic on the necessary ports.

I think it has to do with my tunnel interface (/dev/net/tap0), because
I can ssh across the internet from A, as well as browse the web and
download files, etc. Can anyone provide me some help troubleshooting
this?

Thanks,
Steve