[Dovecot] pop3-login problem

[Oleksii Krykun]

Hi!

I have dovecot-2.2.5 installed as part of postfix+dovecot+mysql+amavisd.
My server has two NICs (Internet and local). /etc/resolv.conf point to ISP DNS. Local names are not resolved.

If ISP link goes to down state I see (after about 1minute) a following error:

Sep 26 15:44:29 pop3-login: Error: master(pop3): Auth request timed out (received 0/12 bytes)

and following informational message:

Sep 26 15:44:29 pop3-login: Info: Internal login failure (pid=12809 id=17815) (internal failure, 1 successful auths): user=<xxx at xxx.xxx> .....

If link is restored (even for a short time) all works fine again. After next down errors are repeated.

I suppose that this is dns issue. Am I wrong?

And I have a following question.
Is it possible to disable dns requests? I haven't external clients. Or I must fix a name resolution e.g. to use a caching dns server?

Thanks.