1. computer setup: Everything running in same server box. the server has Windows 2008 R2 server with domain controller installed hyper-v running running on the server with exchange 2010 running on R2 in a VM 2. Router port forwarding port 25 and port 443 to exchange server 3. everything works fine until this Tuesday, Can not receive external email. internal email, both send and receive works fine, send external email works fine too, but can not receive external email 4. mx record looks fine 5. server configuration/Hub transport/receive connector/Default with "Anonymous user" checked 6. Telnet mail.xxx.com 25 works in the internal network but does not work from outside network Any idea???? I have been working on this for a whole day. No clue. Help!!!

To Add more information. 7. Telnet mail.xxx.com 25 works from computers in internal network 8. Even with firewall turned off on exchange server telnet mail.xxx.com 25 does not work from computer on internet based on packet monitoring tool, telnet request coming to 25 port from outside network but fails somehow ??? Thank you for your help

You sure the router isn't playing up? Nor firewall before the router? Do the Internet test - https://www.testexchangeconnectivity.com/Sukh

You sure the router isn't playing up? Nor firewall before the router? Do the Internet test - https://www.testexchangeconnectivity.com/Sukh

Hi Do you have anything update ? It seems to be betwork error not exchange error. Terence Yu TechNet Community Support