El 08/07/11 14:04, Angel L. Mateo escribió:

El 08/07/11 12:18, Angel L. Mateo escribió:

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Hello,

I have configured two dovecot servers with director acting as lmtp/imap/pop proxy server with 8 dovecot backend servers.

In our test environment we had no problem, but when we migrated to production environment, our mail list server (it delivers mail through lmtp) is having a lot of errors like this:

451 4.4.0 Remote server not answering (DATA output timeout) (in reply to end of DATA command))

Proxy and backend servers are not loaded.

Any idea?

By now, I think I have resolved the problem. We have limited the rate at what list server delivers mail to dovecot. The default postfix configuration is:

lmtp_destination_concurrency_limit = 20 lmtp_destination_recipient_limit = 50

that is,

a maximum of 20 lmtp concurrence connections with a maximum of 50 recipients per connection. We have decrease to 5 and 10 and since then we have no more data output timeout errors.

This wasn't a fix. Although it works temporally and alleviate the 

problem, it didn't completely fixed and I get sporadic errors like:

Jul 11 13:46:25 xenon14 postfix/lmtp[7063]: A0ECA5D49E: to=<user@mydomain.com>, relay=pop.um.es[155.54.212.106]:24, delay=599, delays=569/0/0/30, dsn=4.4.0, status=deferred (host pop.um.es[155.54.212.106] said: 451 4.4.0 Remote server not answering (DATA output timeout) (in reply to end of DATA command))

Any idea of what is the reason for this?

-- Angel L. Mateo Martínez Sección de Telemática Área de Tecnologías de la Información _o) y las Comunicaciones Aplicadas (ATICA) / \\ http://www.um.es/atica _(___V Tfo: 868887590 Fax: 868888337