win2k3 cant access port 100 on other server

Detail:

1. I setup a sockd proxy on port 110 on a public server.
2. My win2k3 cant connect this proxy server. no response anyhow.
3. My win2k3 can send and receive email from other public pop3 server. So it
have accessbility on port 110.
4. My other WinXP under same LAN network can access this proxy without
problem. So its not about nat.
5. I check the IPSec on wi2k3 and set it on Client mode. Which mean permit
any IP and ICMP connection. But problem still.
6. I check the TCP/IP advance setting of network connection on my Win2k3.
the firewall is off. And I have no other firewall at all.

Is there any one have any idea where should I put hand on?

Thanks
Tomasen