[PATCH] Disable reverse DNS lookups

Guilherme Manika guilherme at haxent.com.br
Thu Sep 9 08:23:01 EDT 2010

  Oh, sure.

  Cyrus does a reverse DNS lookup to log the user's domain name to syslog. This adds an overhead to each incoming connection that increases the number of simultaneous connections to the system and may become devastating if there is a problem in external DNS connectivity. We added this when the DNS servers for a large part of our customer base experienced such problems, as that essentially destroyed our POP3 servers.

  Needless to say, this is only a problem for people operating large installations.


Em 09/09/2010, às 08:38, Jeroen van Meeuwen (Kolab Systems) escreveu:

> Guilherme Manika wrote:
>>  This patch adds a "disablereverselookups" option to imapd.conf that
>> disables reverse DNS lookups in imapd and pop3d.
>>  It doesn't affect other services (lmtp, mupdate, etc.) because they are
>> not Internet-facing services and so do not rely on external DNS to work.
>> That's probably acceptable.
> Mind sharing with us what the purpose of this patch is?
> Kind regards,
> -- 
> Jeroen van Meeuwen
> Senior Engineer, Kolab Systems AG
> e: vanmeeuwen at kolabsys.com
> t: +316 42 801 403
> w: http://www.kolabsys.com
> pgp: 9342 BF08
> ----
> Cyrus Home Page: http://www.cyrusimap.org/
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