On Mar 19, 2015, at 7:05 AM, Tara Natanson <[email protected]> wrote:
> > Not sure if this is normal behavior I just haven't come across before or > something new but it seemed like it might be interesting to some folks here. > > A Barracuda device we are sending to is dropping the connection after end of > DATA so we are retrying the message. This happens a few times before the > message finally does get through. The interesting part is that each time the > connection drops after DATA, we are seeing a click and an open (downloading > of images) from that message. > > I've seen AV software do clicks/opens before but it usually accepts the > message first! > > This doesn't seem to be universal across all Barracuda destinations we send > to so I'm guessing it is some individual setting. Sounds like it's doing content-scanning during the connection, but the scan hangs / takes too long, and the MTA side of the box times out the connection. It could just be triggered by variations in system load, but I have seen people deal with an overloaded box taking too long on average to handle inbound mail by reducing the timeouts to "get rid of those slow deliveries' which leads to retries and more load on the box and slower deliveries and more timeouts ... If that is what's going on, the good news is that it's unlikely to deliver that message so you're probably not ending up with duplicates in the inbox. Cheers, Steve _______________________________________________ mailop mailing list [email protected] http://chilli.nosignal.org/mailman/listinfo/mailop
