IP tables and webmail

[Moby]

The current iptables setting of the server:

ACCEPT all -- [eth1] anywhere
ACCEPT all -- [eth0] anywhere
ACCEPT all -- [localhost] anywhere
ACCEPT tcp -- anywhere anywhere tcp dpt:smtp
ACCEPT tcp -- anywhere anywhere [other ports]
DROP all -- anywhere anywhere

My webmail show this:
It was not possible to send this e-mail

After I removed the DROP rule, the webmail can send e-mail again. What ACCEPT rule should I add?

 

[jmstacey]

Here are the ports you need open in your firewall http://help.directadmin.com/item.php?id=71

 

[Moby]

All are opened, but still the same.