I should have known that everything wouldn't go as smooth as glass.  We activated the new DevCentral server at 4:00AM PST today everything seemed to work flawlessly.  We had a bunch of internal folks register and access the site without a problem.  Later in the day we started getting messages like:

“I cannot login.  I've twice tried to 'Reset Password' and have not received my emails!”

Ok, where do we start.  I went on our server and tried out the scenario agian and everything worked.  Oh, I think, it must be a spam filter on the customers site that is blocking the messages.  We got that customer setup manually and let it go.  Then the flood gates opened.  We started getting messages from several partners and customers stating the same problems.

Now it's time to start investigating further.  I configured an email client on the our server to test out SMTP messaging to our mail server and, what do you know, email to external addresses were blocked (internal addresses still worked).

The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'xxx@outsideaddress.com'. Subject 'test message from devcentral', Account: 'xxx', Server: 'xxx.xxx.xxx', Protocol: SMTP, Server Response: '550 5.7.1 <xxx@outsideaddress.com>... Relaying denied. IP name lookup failed [xxx.xxx.xxx.xxx]', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79

It turns out that when we moved our server from the staging to production area, the change in IP address of the server was not registered as a valid client and our mail server thought it was getting an open-relay attempt.

We finally got things working so hopefully the DevCentral users were not too inconvenienced by this temporary hiccup.

I remember the times when you could just pick an email server and point your email client at it and it would just work.  Now you need to worry about open-relay blacklists.