[Dovecot] Dovecot DNS queries its own host many times a second

[Timo Sirainen]

On 25.3.2013, at 3.07, Dominic Malolepszy <dmalolepszy at optusnet.com.au> wrote:

> We have observed that Dovecot appears to make a DNS lookup of its own hostname many times a second. Each Dovecot server in our cluster appears to be doing around 50 queries per second to find out its own hostname. Rsyslog was the first thing we assumed was the cause, however stopping it did not help. Also the fact that at the time Dovecot was doing around 50 logins a second, seemed to correlate with it making these queries. Is there any reason why Dovecot would need to do a lookup of its own hosts IP address every time? Seems like a strange thing to do and not cache its own hostname.

I expected the libc to look it up from /etc/hosts directly.. Anyway, v2.2 does such caching. I'm not sure if it's worth the trouble to backport it to v2.1.