Since migrating to Exchange 2010 a few days ago, I have been unable to get outside SMTP access to work for my smart phone users. I know it's probably related to the rc've connectors and/ or port forward settings on my firewall. I have tried a number of things, but have been unsuccessful. Pop works fine and I have been able to get an outside Outlook client to send SMTP traffic over port 587 succesfully, but haven't been able to get to work on a Windows Mobile, iPhone or Blackberry. Here's my setup and some things I have tried:
Adtran Firewall has a port forward setting to flow Port 25 to a Barracdua and then it flows on to my Exchange 2010 box. Adtran Firewall has port foward setting to send port 80, 443, 990, and 587 directly to Exchange box. OWA access, POP and SMTP setup on external Outlook client pointing to port 587 all work fine. The Default Rc've connector is setup for all IP's. For authentication, TLS, Basic, Offer Basic after TLS, Exchange, and Integrated Windows authentication are all checked. For Perm groups, all except Partner is selected. The Client Rc've connector is setup the same. I do have another Custom Rc've connector that I setup to allow my App svr to relay mail. It is limited to rc've only from the IP address of the App svr though and should not be conflicting with anything.
I can send email from my Win Mobile phone to my internal domain successfully, but when I try to send them to other domains, I get the error 550, No such domain at this location. I would look at using ActiveSync, but I am using a Self-signed cert. I may get a 3rd party cert in the future, but I just need to get the SMTP working for mobile users for now. I have tried different SMTP and SSL settings on my phone and have tried to play with settings on the rc've connectors, but have not been able to resolve yet. I have researched the 550 error, but have not been able to find a solution that has helped me. Thanks in advance for your help.