trouble with external clients and SMTP

[progman1010]

hello. I have exchange 2003 with a remote user on Outlook 2003. I have set up his account so that he can connect to my exchange server through POP3 and download his messages (everyone else is on straight exchange mailboxes). However, he can't send messages through the server via SMTP. This is the first time I've done this type of thing with exchange, so I'm not sure what to ask for and where to hunt for the settings.

Any advice is greatly appreciated.

 

[rjs]

Your remote Outlook client probably connects through an ISP. Most ISP's block SMTP traffic to reduce spam. You must either point his outbound SMTP server to his ISP or configure RPC over HTTP for Outlook:

http://www.msexchange.org/tutorials/outlookrpchttp.html

 

[ShackDaddy]

You can test to see if what RJS is suggesting is true by going to the command line on that guy's workstation and doing a "telnet yourserver.domain.com 25".

If you get a response, and connect to your server, then it's not port blocking, but it's 90% likely that portblocking at your ISP is the problem.

Many smaller ISP's allow you to remove port blocking, so you can ask the user's ISP about that, but the larger ISP's won't allow it.

Dave Shackelford
Shackelford Consulting

 

[progman1010]

i understand what you mean there. i can try that.

is there a way for me to change the port of my exchange SMTP server? perhaps i can work around the generic ISP restrictions as i have done in the past.

 

[ShackDaddy]

You could create an additional virtual SMTP server in the Exchange\Protocols\SMTP folder and configure it to listen on port 2525 or something, open that in your firewall, and then have the client use that port for outbound SMTP connections to your server.

Dave Shackelford
Shackelford Consulting

 

[progman1010]

i think I'm having more of an issue with this than just my isp blocking the port. I tried to telnet to the SMTP server on several different ports with no luck. Telnet to port 110 worked fine.

My SBS server is using NAT firewall- could this have anything to do with it?

 

[ShackDaddy]

You should go into the local Windows firewall and make sure there is an exception for the alternate ports you've created.

Dave Shackelford
Shackelford Consulting