Merak Email Server: Distributed Domain


IceWarp Ltd., the creators of widespread and popular Merak Email Server have announced a minor release 8.3.5, introducing a new type of domain - the distributed domain. Distributed domain concept is targeting systems with heavy mail traffic and solves the problem of system slowdown due to increased mail traffic.

Full text

PRAGUE 12/08/2005: Merak Email Server of version 8.3.5 and further comes with new and unique type of domain implemented, distributed domain. Generally speaking, distributed domain supports multiple hosts in the domain value and when a mail message is being received the mailserver is querying each host for recipient (RCPT TO) and tries to deliver the incoming message. Each of the hosts (each server) is hosting part of the user accounts database. The query is performed though SMTP command VRFY. Please do not disable this command in your Merak Email Server in order to be able to distribute the incoming messages across multiple hosts.

In case recipient is found on any queried host server, the message is automatically delivered. On the other hand, in case some of the hosts is unavailable or there is a connection error in the moment of message receiving an temporary error asking for later retry is returned and the message is forwareded to the next host in the list. So if one or more servers is not available and the recipient was not found on the remaining servers a temporary error is returned.

Finally, if all hosts are reachable and the recipient is not found on any server (the last server host from the distributed list respond with user unknown) the message is rejected with permanent 5xx error.

Distributed domain concept is thus targeting systems with heavy mail traffic and solves the problem of system slowdown due to increased mail traffic. Please note, that the hosts do not have to be on single location and so, corporations having branches on several locations can also take advantage of distributed domain system.

To concretize the previous let's think of an example:

Assume we have following DNS entries:
IN MX 10
IN MX 20
IN MX 30  IN A IN A IN A     

And now we create the following distributed domains in the Merak Email Server on every of the three servers: 

So as you can see, using distributed domains is very easy, effective and it simplifies load balancing of multiple machines and thus improves stability, serviceability and throughput of your production mail server!

About IceWarp

IceWarp, Ltd. was started in 1999 with the development of Merak version 1. Merak’s exceptional product stability, performance, reliability and value quickly got the attention of business and ISP customers. This has produced strong sales and double digit sales growth year after year. During this time, IceWarp has maintained a technology leadership position by continuing to advance Merak through many industry-firsts, including:

  • First mail server supporting SSL
  • First mail server with Web mail
  • First integrated multi-threaded antivirus
  • First integrated anti-spam
  • First GroupWare with API (ODBC based)
  • And now, the first server with integrated FTP and Web server capabilities

Contact address

IceWarp Ltd. is located at City House, 6 Karaiskakis street, CY-3040 Limassol, Cyprus