Totally stumped - very long post

[Olivier Nicole]

> Now here's a traceroute from the server to my Mac at home (actually to the =
> 
> IP of the dsl router:
> traceroute 66.140.63.124
> traceroute to 66.140.63.124 (66.140.63.124), 64 hops max, 40 byte packets
>  1  * * *
> traceroute: sendto: Host is down
>  2 traceroute: wrote 66.140.63.124 40 chars, ret=3D-1
>  *traceroute: sendto: Host is down
> traceroute: wrote 66.140.63.124 40 chars, ret=3D-1

Would be usefull to try to traceroute from your mac to your server:
comparing both traceroute helps to see where the route is blocked.

A ping in both direction will help too.

A traceroute to another IP in 66.140.63/24 network may help. To
another IP in 66.140/16. To another IP in 66/8.

Traceroute from and to the webmail machine could help too, find the
difference, understand why there is difference and then you have your
problem located.

Then install wireshark (/usr/ports/net/wireshark-lite/) on the server
from the ports and see what it says when you are trying to browse the
server? Can you see the SYN packet? Does the server send the SYN/ACK
packet?

Install wireshark on your Mac client and do the same test, does
yourclient send the SYN packet? Do you see the SYN/ACK sent bythe
server?

Desactivate the firewall on both machines.

Olivier