iMS authenticated relay not working

Hi

I am using iMS 5.1 behind a firewall. The server has an internal LAN ip address, also has a static global ip assigned on the firewall.

I am able to send mails to the internet from my LAN after smtp authentication. Also incoming mails are coming in without an issue.

But when I try to use my server as a relay (after smtp authentication) it just doesn't work and gives realying denied.

When I telnet to my server from outside on port 25 and issue EHLO, I get a 500 5.5.1 Unknown command "XXXX" specified.

when I issue AUTH LOGIN again I get the same error above.

why is this happening? I can use the same features while connecting from my LAN.

What do I need to change in my setup to enable this?

Pls help me out!!

Thanks and Regards,

Sanvir Jham

[833 byte] By [706683] at [2007-11-25 8:32:24]