Can't receive external mail using sendmail

Installing, Configuring, Troubleshooting server daemons such as Web and Mail
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joeshmo
Posts: 4
Joined: 2013/06/17 15:22:19

Can't receive external mail using sendmail

Post by joeshmo » 2013/06/24 12:02:02

Hi Gurus,

I need some help configuring sendmail to be able to receive external mail from say "gmail".

I've already tried opening iptables:
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 25 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m udp -p udp --dport 25 -j ACCEPT

and I edited the sendmail.mc to:

dnl # DAEMON_OPTIONS(`Port=smtp, Name=MTA')dnl


When I run netstat i get:

netstat -nl

tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN

I don't get why i can't receive any emails from the outside still when i check "mail" i have none. If i try to scan port 25 from the outside also, i get that port 25 is not responding (maybe its because sendmail is already using it?) I also tried adding an addr field in sendmail.mc to include my domain ip but to no avail so i took it off and now it's 0.0.0.0.
The DNS Ip addresses are also in the resolv.conf file so I don't think thats the problem.

I also tried:

iptables -I INPUT -p tcp --dport 25 -j ACCEPT
iptables -I OUTPUT -p tcp --sport 25 -j ACCEPT

but no cigar..

I'd be glad if someone could help me out I've been pulling my hair out all day

tigalch
QA Team
Posts: 522
Joined: 2012/06/23 17:28:41
Location: Austria

Can't receive external mail using sendmail

Post by tigalch » 2013/07/11 17:02:07

What does the maillog on your host say? And second, when you try to connect, do you get an established TCP-Session (udp is not required for SMTP)? If the session fails it might be an iptables problem.

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