Have a new Exchange 2010 up to date on an existing 2008R2. Server is a little light on the ram but will be ordering more soon.
Unable to receive external emails but can send externally and send/receive internally. MX and A records appear to be correct (except that the MX priority is 0 not 10 like usually see). Made sure that the external ports are open (see 25 via canyouseeme.org) and forwarded. I double checked all settings against 2 known good servers and everything appears to be fine. Appear to be able to Telnet into the server internally but not from the internet?.? Unable to hit OWA either by MX or IP. Ran built in diags and nothing appears to be wrong. Do not use any shell commands at all so I only check using older methods (please be extremely explicit if want me to test using shell).