I host my web site on Go Daddy, and have e-mail through Uplink Earth.  Uplink Earth supports outgoing SMTP on ports 25 and 1025. I can send mail just fine on 1025, using my Uplink Earth credentials, but it doesn't work at all on port 25 (even using Microsoft Outlook). This is a problem because Go Daddy doesn't allow port 1025 to be used. The only common port is 25.

I also have a DNN application directly on the Uplink Earth hosting, which is also unable to send e-mail using port 25.

Uplink Earth insists that my ISP is blocking port 25... But when DNN or any ASP.NET page generates an outgoing SMTP, doesn't it do so on the host machine instead of the client?

I checked my firewall, and router to make sure I wasn't blocking port 25, and it's not. What in the world could be wrong??

Thanks in advanced,
Robert

My recollection is that GoDaddy blocks port 25 on its servers, but allows outbound 587.  I assume 1025 is available, but with them who knows.

So, Antony's advice is excellent, except you're going to need to be using 1025 instead.  As he said, if you are able to telnet with 1025 on a non-GoDaddy machine, but cannot on the server itself, you know you have a blocked port at their end.

Brandon

First of all, thanks to everyone for your responses. Here is what eventually happened:

From my understanding, Go Daddy blocks all outgoing SMTP traffic (from web applications) unless it goes through their relay server, regardless of the port. Not good... HOWEVER, their relay server supposedly allows up to 1000 relays per day, which I can live with.

I seem to get different answers everytime I call, so this is a combination of tech support information and experimentation.

Robert