-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 08/28/13 11:02, Oliver Hitz wrote: > On 28 Aug 2013, Michael Richter wrote: >> Trying 195.186.227.50... Connected to mxzhh.bluewin.ch. Escape >> character is '^]'. 421 4.4.5 Service unavailable, concurrency >> limit reached. > > We see the mail queues growing with undeliverable mails for > bluewin.ch. > > The same also happened on monday before Swisscom was unreachable. > This reminds me of 2011 when they were attacked.
There was an attack and maybe it has amplified this issue but so far the root cause of the problem was a strange behavior of the bluewin MX load balancer (LB). For unknown reasons, LB probes for MX server have failed although each MX server was running fine. The LB started removing "failed" MX server from MXIN pool for several minutes. The pool got smaller and smaller. The load on the remaining pool was increasing until the concurrency limit was reached. This issue was resolved at moon (GMT+2). An investigation is underway to find out how this happened. Regards, Tom -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (FreeBSD) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlIeBxUACgkQGCwkYTI5tyA5GACcCrgoG5zjFAI8N2C08m7xRWoS baIAoIDxcUIK/LxxXvqCo3tVEdOSxEAE =Sx0p -----END PGP SIGNATURE----- _______________________________________________ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
