Question : 2003 SBS blocking incoming SMTP from firewall 0x800CCC0E

I've worked on this for 6 hours trying various things and cannot for the life of me figure out why this server is doing what it's doing.  
It's a 2003 SBS w/Exchange.     I can POP into it externally, but cannot send mail.. I get that stupid 0x800CCC0E error
Port 25 is up and listening, I can sent email out though web access OWA from external.
I can also send/receive mail Internally using OE and pop setup.. that's what baffles me.

My firewall (Linksys) has port 25 open, even did a port scan to confirm.

I cannot Telnet to the server using port 25... states it cannot connect.  This is from external AND internal .. even straight up on the server itself using it's IP

It's like something is kind of blocking traffic, but not.     I had Mcafee on there, removed it, same issue.    
No windows firewall set up on the NIC either.

Thoughts??

Answer : 2003 SBS blocking incoming SMTP from firewall 0x800CCC0E

Good!  So you can now `telent localhost 25`, and your ISP says that they have TCP 25 open, and you have tested the open port (with some web-based tool, I presume).

If whatever port check tool you used sees TCP 25 open, then your router is doing what it's supposed to and your internal server is responding.

But you can't `telnet 68.15.xxx.xxx 25` from *outside*?  Now I'm confused.

Let's try something.  Visit this website:  http://www.zoneedit.com/smtp.html  and have a SMTP test session.  Since you won't publish your IP address (which is respectable), then this is the next best thing.  Publish the results here for us to see.