A couple of days ago the enet.gr domain went missing. I observed this because of a call I got from our press office where a user complained that sending mail to journalists was not possible: “I can email all the world, except journalists”. The mail logs showed that:
Feb 17 13:08:26 ns sm-mta: q1HB5o4Y001215: lost input channel from host.name [x.x.x.x] to mta after rcpt
So what was wrong? Because of delays in DNS server responses regarding enet.gr, Thunderbird timed out and dropped the connection (the problem appeared to be Thunderbird specific). My quick hack of the moment because I was on the road was to point enet.gr to 127.0.0.1 in the SMTP server’s /etc/hosts (I was on the road with limited connectivity). A far better solution is to increase the value of mailnews.tcptimeout preference.