Mails are not delivering from Mail Queue Manger and throwing connection refused error then just follow the following steps and add the iptables rules:
1) Go to shell of Linux server.
2) service iptables save
3) service iptables stop
4) Add following rules
iptables -A INPUT -p tcp –dport 953 -j ACCEPT
iptables -A INPUT -p tcp –dport 53 -j ACCEPT
iptables -A INPUT -p udp –dport 53 -j ACCEPT
iptables -A INPUT -p udp –dport 953 -j ACCEPT
5) service iptables start
