On Sat, Dec 01, 2012 at 09:31:41PM +0100, IMAP List Administration wrote:
> At any rate, we periodically see (1-5 times per day) a "Client host rejected:
> cannot find your hostname" rejection, followed by a successful retry from the
> remote MTA. When we check the DNS records, they always appear to be in order.
> The remote MTAs belong to various organizations, but typically ones where one
> would expect the DNS config to be well-maintained. (see bottom for an example
> rejection and the ensuing successful retry).
If you see this for all remote MTAs, the problem is with your DNS
software or network connectivity. If it is just for certain remote
MTAs and not the rest, the problem is with their DNS.
> 1) is it possible that we are observing a bug in postfix in conjunction with
> DNS-queries? Are there any such known bugs?
No such bugs are known, likely or observed by other sites. DNS
clients are much simpler than DNS servers, look for bugs in DNS
configuration then the DNS servers or in the network.
> 2) can someone give me a tip on how to configure BIND to log the information I
> need to figure out why DNS lookups may be failing intermittently, and how to
> read it properly?
This is not simple. First use your Postfix logs to find out which domains
or IPs exhibit the transient errors, and whether such errors are
random or tied to specific domains.
--
Viktor.
>
