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Hey everyone
i have an exchange server configured behind my untangle firewall
i have port forwarded ports 443 and 25 to my exchange server
i can hit OWA without issue (443) but no mail is coming through. if i try and telnet from the internet on port 25 i just get a connection timed out
Connecting To mail.tingateit.xyz...Could not open connection to the host, on port 25: Connect failed
i can telnet internally to the exchange server without issue
Has the mail smtp worked with the same ISP before? Most ISPs block port 25 by default. I would check reports for the mail server IP to see if any of the apps are blocking the incoming connection also.
I have two internet links
a fixed line, and a business 4g services, have tried via both, same result, i have checked with the fixed line ISP and ocnfirmed 25 inbound is allowed
Ingress TCP 25 is a port forward that looks identical to your 443 forward. Heck, you could just use a comma separated list for your destination port flag, and do both TCP 443 and 25 in the same rule.
If you do that, and 443 works while 25 doesn't... your ISP is lying to you.
TCPDump can prove it, you just have to ask it to watch for dst port 25 while you test. If you see the packets but the service isn't responding well... time to go smack your mail server.