On 04.03.2012 19:24, Stanisław Findeisen wrote: > On 2012-03-04 11:26, Michael Tokarev wrote: >> On 04.03.2012 13:30, Stanisław Findeisen wrote: >>> On 2012-03-04 09:20, Stanisław Findeisen wrote: >>>> Hi! >>>> >>>> I am running a small Postfix server, and for a couple of hours I've been >>>> getting: "host ... refused to talk to me: 421 service not available >>>> (connection refused, too many connections)" for all the outgoing mail, >>>> all destination servers. >>>> >>>> What's wrong? >>>> >>>> I wasn't even able to subscribe to this mailing list: >>>> >>>> Mar 4 00:41:38 k8ux postfix/smtp[2987]: 1462B1F2505: >>>> to=<[email protected]>, relay=mail.cloud9.net[168.100.1.7]:25, >>>> delay=417, delays=417/0.02/0.06/0, dsn=4.0.0, status=deferred (host >>>> mail.cloud9.net[168.100.1.7] refused to talk to me: 421 service not >>>> available (connection refused, too many connections)) >> >> This smells very much like your outgoing SMTP connections are being >> trapped by your ISP and redirected to _their_ SMTP server. > > Wha... what a... ??! 8-O > > You say that mail.cloud9.net[168.100.1.7] was in reality my ISP's > network node? I.e., they are doing some kind of man in the middle attack > / IP address spoofing? > > Why do you think they should be doing crap like that??!
It is very common practice among consumer ISPs worldwide. Either redirecting outgoing SMTP (port 25) to their own mailserver, or merely disabling (dropping) outgoing SMTP completely. This is in order to stop mass spamming by bots/trojans installed in huge quantities on client machines. > It just started to work after some 15 hours or so. ALL destination > servers (the whole queue has been sent out). That's probably good. /mjt
