Open Relay for Domains since 8.4.0 upgrade

[Jayson]

Hello,

Shortly after upgrading to 8.4.0 from 8.3.0 I started receiving calls from customers who are missing emails. After some debugging I found hosted domains using my email server showed the server as an open relay. Even though, the same lookup on my domain with the same email server showed no Open Relay.


Anybody else having this problem?

 

[dirty@]

The most probably you have Server > Mail > POP3 authorization enabled.

 

[Jayson]

POP3 authorization is enabled and the lock time is 20min and smtp is also enabled. I have sinced noticed that the domains having problems did not have a Postmaster or Abuse email address. After I added the aliases to my customers domains, the dns report stopped reporting the domains as open relays... I'm just waiting to see if the email is still being rejected.

 

[Jayson]

Email was still being rejected, however I think the problem has been found. It would seem one of the MAPS rbl lists was rejecting email and it's made more difficult to find since there is no record of the rejection in my maillog file. By removing MAPS support and then adding back one rbl at a time I found the one which was rejecting and removed it.

 

[datahaus]

i had alot of problems with short mailbox names and some hackers could use the server as open mail relay, after hours of investigating it seems the "-Rt0" caused the problems in /etc/xinetd.d/smtp_psa (and /etc/xinetd.d/smtps_psa) ... try to remove that if it is there and restart xinetd with "service xinetd restart"

PS: i read in another thread that it is now "--Rt0" to disable reverse lookups, but not tested