On Thu, Jul 21, 2011 at 06:55:35PM +0000, Eric Smith wrote:
> The problem is this yahoo and yahoo alone fails to make connections, the
> problem is random,most emails come through just fine, the specific
> failures are not repeatable. But an parker of ours uses yahoo business
> serves for their email, they are getting timeout bounces on 1 in 10 emails
> sent to us.
Yahoo have closed the connection by the time you're sending the 220
banner. Therefore, either they're broken, or your DNS is slow, or
all your connections are busy (not running enough smtpd processes).
Often synchronous logging is the cause of poor email throughput on
new Linux installations. Yahoo are perhaps less patient than other
senders.
You need to tcpdump some of the Yahoo sending IPs that are timing out,
and see how long it takes for them to give up and how long it takes
your servers to respond with 220 after TCP connect.
--
Viktor.
