[Dovecot] Connection queue full on 2.0.8

[Patrick McLean]

Hi,

I can't find any references to this problem on 2.x. I upgraded to 2.0.8
last night, and now I am getting these errors in the logs (along with
the server refusing new connections):

> Dec  8 09:46:52 orford dovecot: imap-login: Disconnected: Connection queue full (no auth attempts): rip=x.x.x.x, lip=x.x.x.x, TLS
> Dec  8 09:47:16 orford dovecot: imap-login: Disconnected: Connection queue full (no auth attempts): rip=x.x.x.x, lip=x.x.x.x, TLS handshaking

I have unsuccessfully tried to tweak my settings to prevent this
problem, and any help would be appreciated. The server has plenty of
power for increasing process limits, etc.

Below is the output of "dovecot -n". We have users with some _very_
large mailboxes (~400 000 messages) so some of the limits might appear
excessive.:

> # 2.0.8: /etc/dovecot/dovecot.conf
> # OS: Linux 2.6.35-gentoo-r5+ x86_64 Gentoo Base System release 2.0.1 
> auth_cache_size = 10 M
> auth_mechanisms = plain login
> auth_worker_max_count = 80
> default_client_limit = 2048
> default_process_limit = 256
> default_vsz_limit = 512 M
> first_valid_uid = 125
> last_valid_uid = 20000
> listen = 127.0.0.1 x.x.x.x
> login_greeting = IMAP ready.
> mail_location = maildir:~/Maildir
> managesieve_notify_capability = mailto
> managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date
> mdbox_rotate_size = 10 M
> namespace {
>   hidden = no
>   inbox = yes
>   list = yes
>   location = 
>   prefix = 
>   subscriptions = yes
>   type = private
> }
> namespace {
>   hidden = yes
>   list = no
>   location = 
>   prefix = INBOX.
>   subscriptions = yes
>   type = private
> }
> namespace {
>   hidden = no
>   list = yes
>   location = maildir:/home/shared/Maildir:CONTROL=~/Maildir/control/shared:INDEX=~/Maildir/index/shared
>   prefix = shared.
>   subscriptions = no
>   type = public
> }
> passdb {
>   args = failure_show_msg=yes
>   driver = pam
> }
> plugin {
>   quota = fs:User quota:user
>   quota_warning2 = storage=80%% quota-warning 80 %u
>   sieve = ~/dovecot.sieve
>   sieve_dir = ~/sieve
> }
> protocols = imap pop3
> service auth {
>   unix_listener /var/spool/postfix/private/auth {
>     group = postfix
>     mode = 0666
>     user = postfix
>   }
> }
> service imap-login {
>   process_min_avail = 5
> }
> service imap {
>   process_limit = 2048
> }
> service managesieve-login {
>   inet_listener sieve_deprecated {
>     port = 2000
>   }
> }
> service pop3 {
>   process_limit = 128
> }
> ssl_cert = </etc/ssl/dovecot/imap.crt
> ssl_key = </etc/ssl/dovecot/imap.key
> userdb {
>   driver = passwd
> }
> verbose_proctitle = yes
> protocol lda {
>   mail_plugins = sieve quota
> }
> protocol imap {
>   mail_max_userip_connections = 10
>   mail_plugins = " quota imap_quota acl"
> }
> protocol sieve {
>   mail_max_userip_connections = 10
> }
> protocol pop3 {
>   mail_max_userip_connections = 3
>   pop3_uidl_format = %u-%v
>   ssl_cert = </etc/dovecot/certs/pop3.pem
>   ssl_key = </etc/dovecot/certs/pop3.key
> }