Mac Server - Postfix Issue on certain ISP or Network
I have Mac Server and MAMP running as my local server, and have set up Postfix in MAMP to enable outgoing mail.
I have the smart host set as gmail.com
When I connect the machine to the internet using my mobile phone network (vodafone), all works perfectly.
However, when I connect the machine to the internet with my normal ISP, through my LAN, postfix returns the error:
Host or Domain name not found. Name service error for name=gmail.com type=MX Host not found, try again
I have tried it changing the smarthost to the ISP's mail.isp.com, same issue.
Using the command dig gmail.com (or indeed dig myisp.com) it ONLY returns A names, no MX. A 'dig gmail.com MX' (or dig myisp.com MX) returns a timeout.
My LAN is a router behind a modem, nothing more than that.
So, where should I start?
The fact it works on my vodafone ISP suggests it's either an issue with my normal ISP blocking something? or my local network set up?
Any suggestions, most appreciated.