Hi all;

I've upgraded a ring of dovecot directors from 2.2.15 to 2.2.36. After the upgrade I've got some instability: a few time per day per server, seemly at random, the auth process stop responding and the clients cannot authenticate any more:

Sep 6 14:45:51 imap-front13 dovecot: pop3-login: Warning: Auth process not responding, delayed sending initial response (greeting): user=<>, rip=xx.xx.xx.xx, lip=xx.xx.xx.xx, TLS, session=<1HVqRTN10MNTie+S>

I can't figure it out.... Any hints?

This is my configuration:

# 2.2.36 (1f10bfa63): /usr/local/etc/dovecot/dovecot.conf

# OS: Linux 3.2.0-4-686-pae i686 Debian 7.11

# Hostname: imap-front13.mailfarm.interac.it

auth_mechanisms = plain login digest-md5 cram-md5 apop scram-sha-1

auth_verbose = yes

auth_verbose_passwords = plain

auth_worker_max_count = 50

base_dir = /var/run/dovecot/

default_login_user = nobody

director_doveadm_port = 9091

director_mail_servers = 192.168.1.142 192.168.1.143 192.168.1.144 192.168.1.145 192.168.1.216 192.168.1.217 192.168.1.218 192.168.1.219

director_servers = 212.183.164.157 212.183.164.158 212.183.164.159 212.183.164.160

listen = *

passdb {

args = /usr/local/etc/dovecot/sql.conf

driver = sql

}

protocols = imap pop3

service director {

fifo_listener login/proxy-notify {

mode = 0666

}

inet_listener {

port = 9090

}

unix_listener director-userdb {

mode = 0600

}

unix_listener login/director {

mode = 0666

}

service imap-login {

executable = imap-login director

service_count = 0

vsz_limit = 128 M

}

service pop3-login {

executable = pop3-login director

service_count = 0

vsz_limit = 128 M

}

ssl_cert = </usr/local/etc/dovecot/qcom.wildcard.pem

ssl_cipher_list = ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA

ssl_dh_parameters_length = 2048

ssl_key = # hidden, use -P to show it

ssl_parameters_regenerate = 1 weeks

ssl_prefer_server_ciphers = yes

ssl_protocols = !SSlv2 !SSLv3

syslog_facility = local5

userdb {

driver = prefetch

}