Issue with one user only, exceeding connections

Jeremy Schaeffer kb9mfd at phonesplus.biz
Wed Jun 8 19:14:23 UTC 2022


I keep having this issue with one user, and I have to restart dovecot 
several times a day to clear it. What I have is a postfix / dovecot mail 
server (Centos 7) and about a dozen users. All mailboxes are imap ssl. I 
monitor about 4 mailboxes on my computer and tablet. I use Thunderbird 
on the computer (cache connections at 2) and K9 on the tablet, but one 
user of the four I keep getting "Maximum number of connections from 
user+IP exceeded" and I have the maximum at 50 
"(mail_max_userip_connections=50)" so its hard for me to believe I am 
actually exceeding it unless dovecot/client is not dropping connections 
and keeps starting new ones until it reaches the maximum, but again, 
only for one user, even though I am monitoring 4 on the same devices. 
Any idea how to troubleshoot this? I don't know if I should be looking 
at dovecot or the clients, or what I need to look for. It's been going 
on since I put this server in use over a year ago. I also have issues 
with Outlook clients disconnecting, just outlook, is there any 
recommended settings to make Outlook work smoother?

Thanks! - Jeremy

Config -

# 2.2.36 (1f10bfa63): /etc/dovecot/dovecot.conf
# OS: Linux 3.10.0-1160.11.1.el7.x86_64 x86_64 CentOS Linux release 
7.9.2009 (Core)
# Hostname: ***
auth_mechanisms = plain login
debug_log_path = /var/log/dovecot_debug.log
first_valid_gid = 500
last_valid_gid = 600
last_valid_uid = 600
listen = *
mail_location = maildir:~/Maildir
mbox_write_locks = fcntl
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 = INBOX.
   separator = .
}
passdb {
   driver = pam
}
pop3_uidl_format = %f
protocols = imap lmtp
service auth {
   unix_listener /var/spool/postfix/private/auth {
     group = postfix
     mode = 0660
     user = postfix
   }
}
service imap-login {
   inet_listener imap {
     port = 143
   }
   inet_listener imaps {
     port = 993
     ssl = yes
   }
   process_min_avail = 1
   service_count = 0
}
service imap {
   process_limit = 1024
}
service lmtp {
   unix_listener lmtp {
     mode = 0666
   }
}
ssl = required
ssl_cert = <***
ssl_cipher_list = ECDHE-RSA-CHACHA20-POLY1305:ALL:!LOW:!SSLv2:!EXP:!aNULL
ssl_key =  # hidden, use -P to show it
ssl_prefer_server_ciphers = yes
userdb {
   driver = passwd
}
protocol imap {
   mail_max_userip_connections = 50
}



More information about the dovecot mailing list