fsockopen() from 127.0.0.1 is not working

Question

I'm trying to connect to an SMTP server from my local machine (127.0.0.1). I'm able to connect to other SMTP servers, but this one in particular will not connect from my local machine, it will connect however from 4 other remote servers I have tested on.

I receive the following error trying to connect from my local machine:

Message: fsockopen() [function.fsockopen]: unable to connect to mail.domain.com:25 (A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. )

Would anyone know what may cause the server to not allow connections from 127.0.0.1, It's not behind a firewall and postfix is accepting all networks.

Thank you!

Answer 1

I'd guess the SMTP server is not bound to the loop-back device. Check its configuration. You usually signal you want it to listen to all interfaces by specifying the address 0.0.0.0 (may be different for IPv6).

Answer 2

This was an ISP issue, which blocked port 25.