On Thu, 9 Sep 2010, Guilherme Manika wrote:

 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.

or very small ones that do not have reverse DNS properly setup (not an uncommon situation)

David Lang

Guilherme


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: vanmeeu...@kolabsys.com
t: +316 42 801 403
w: http://www.kolabsys.com

pgp: 9342 BF08
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