Background.
A while back I upgraded my phone to one currently using Android 4.1.2 and K9 mail 4.409. This phone/MUA combination seems at times to go crazy making IMAP connections.
At first, I had mail_max_userip_connections = 30 (my largest imap account has 19 folders). The issue I had at that time was multiple errors like
Oct 14 17:45:16 sbh16 dovecot: imap-login: Maximum number of connections from user+IP exceeded (mail_max_userip_connections=30): user=<xxx>, method=PLAIN, rip=xx.xx.xx.xx, lip=xx.xx.xx.xx, TLS, session=<c63x5bzowQBi0uQR>
I then set mail_max_userip_connections = 50
This greatly reduced but didn't completely eliminate these messages, but then I would see multiple
Oct 31 16:13:40 sbh16 dovecot: master: Warning: service(imap-login): process_limit (100) reached, client connections are being dropped
and
Oct 31 16:13:40 sbh16 dovecot: imap-login: Disconnected: Connection queue full (no auth attempts in 4 secs): user=<>, rip=xx.xx.xx.xx, lip=xx.xx.xx.xx, TLS handshaking, session=<s26xmRHqVQBi0uQR>
followed finally by
Oct 31 16:13:40 sbh16 dovecot: imap-login: Panic: file client-common.c: line 190 (client_destroy): assertion failed: (!client->authenticating)
Oct 31 16:13:40 sbh16 dovecot: auth: Warning: auth client 19669 disconnected with 1 pending requests: EOF
Oct 31 16:13:40 sbh16 dovecot: imap-login: Fatal: master: service(imap-login): child 19669 killed with signal 6 (core not dumped - add -D parameter to service imap-login { executable }
I then set default_process_limit = 200, and things seem to have settled down, but I thought the panic should be reported.
Possibly this is relevant - the above only seem to occur when the phone is connecting via wifi and possibly only when the phone has just switched from the phone data network to wifi.
Current doveconf -n # 2.2.6: /usr/local/etc/dovecot/dovecot.conf # OS: Linux 2.6.18-8.1.14.el5 i686 CentOS release 5 (Final) auth_mechanisms = plain apop login auth_worker_max_count = 5 default_process_limit = 200 mail_location = mbox:~/Mail:INBOX=/var/spool/mail/%u mail_privileged_group = mail mbox_write_locks = fcntl dotlock namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { args = /usr/local/etc/dovecot.passwd driver = passwd-file } passdb { driver = pam } protocols = imap pop3 service auth { unix_listener /var/spool/postfix/private/auth { mode = 0666 } } ssl_cert = </etc/httpd/conf/ssl/combined.crt ssl_key = </etc/httpd/conf/ssl/www.grizz.org.key userdb { driver = passwd } protocol imap { mail_max_userip_connections = 50 }
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan