March 21, 2013

Alimex SMTP server rules

Posted in Mail at 2:45 pm by Administrator

May 11, 2015 Edit: We added a new entry to the RBL block list, which is linked to BarracudaCentral and since May 9th we use their BRBL list too.

July 18, 2014 Edit
: Recently we added an additional level of inspection and security by activating a DNS <-> rDNS check of the clients that connect to our server. This should reduce the level of SPAM, because any dynamic or static IP of a host, that is not supposed to and configured to send mail would not have such 1 to 1 consistency in the hostname.

The request is rejected when:
1) the client IP address->name mapping fails
2) the name->address mapping fails
3) the name->address mapping does not match the client IP address.

Currently the reply is 450 and it is always 450 in case the address->name or name->address lookup failed due to a temporary problem. Administrators should check their logs and look for a response “450 4.7.1 Client host rejected: cannot find your hostname, [<IP address>]”.

Original post:

As of today, we implemented new RBL lookups in our SMTP server to protect our clients better from outside SPAM and to reduce the load on our SMTP server. The RBL zones list has been updated and the following zones are currently included in our checks:

We believe that these zones are trustful enough and rely on the information in the lists to be correct. If you want to check your IP or learn more about these zones, you can use the following website: You can use each zone’s own site to get delisted, if your IP is listed there. If you feel our use of any of the zones disrupts your work process, you can contact us at our abuse e-mail.