'Could not connect to SMTP host'

guysmiley

Member
Sep 6, 2008
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0
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Greetings,

Does Exim need to be enabled for SMTP to function? SMTP is allowed through our Firewall... Is there anything else that must be enabled for SMTP to work?

Tx!
 

mtindor

Well-Known Member
Sep 14, 2004
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inside a catfish
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Root Administrator
Greetings,

Does Exim need to be enabled for SMTP to function? SMTP is allowed through our Firewall... Is there anything else that must be enabled for SMTP to work?

Tx!
Yes, Exim definitely needs to be active for SMTP to work. By default it will be listening on TCP 25. Make sure your firewall is allowing ingress TCP 25.

ps auwx|grep exim - see if it's running

telnet main.ip.address 25 - you should see your server banner pop up.

NOTE: If you are testing from a remote location (such as a machine on a DSL or Cable line), you may find that you are blocked from accessing port 25 (SMTP) of the server, but not because of the server - instead, the ISP may be blocking outbound port 25 (forcing theri customers to use the ISP mailserver for outbound delivery).

Most decent ISPs today block port 25 outbound by default for residential / non-static connections so that if a machine on one of those connections gets compromised and starts sending spam, it won't go anywhere.... except maybe through the ISP's own mailserver, which they then can track and take action on.

There are a million different ways to verify that exim is started and listening on port 25... one quick and dirty way is:

lsof -n|grep TCP|grep smtp

some others are:

ss|grep smtp

netstat -an|grep LISTEN|grep ':25'


With any of the above three commands you should see some at least one entry showing that SMTP is active.

Mike