[Dovecot] 2.0.14 IPC client_limit reached error

Tom Pawlowski tompru at jla.rutgers.edu
Wed Sep 28 17:09:17 EEST 2011


Hi Timo,

Upgraded to 2.0.14 last night for the director-related features and I noticed
an oddity in the logs:

Sep 28 09:53:21 director2 dovecot: master: Warning: service(ipc): client_limit reached, client connections are being dropped
Sep 28 09:53:56 director1 dovecot: master: Warning: service(ipc): client_limit reached, client connections are being dropped
Sep 28 09:54:23 director2 dovecot: master: Warning: service(ipc): client_limit reached, client connections are being dropped
Sep 28 09:55:07 director1 dovecot: master: Warning: service(ipc): client_limit reached, client connections are being dropped
Sep 28 09:55:24 director2 dovecot: master: Warning: service(ipc): client_limit reached, client connections are being dropped
Sep 28 09:56:08 director1 dovecot: master: Warning: service(ipc): client_limit reached, client connections are being dropped
Sep 28 09:56:25 director2 dovecot: master: Warning: service(ipc): client_limit reached, client connections are being dropped
Sep 28 09:57:10 director1 dovecot: master: Warning: service(ipc): client_limit reached, client connections are being dropped
Sep 28 09:57:26 director2 dovecot: master: Warning: service(ipc): client_limit reached, client connections are being dropped

These warnings are only being printed out by the directors. Both the directors
and imap/pop3 servers have init scripts with the following ulimits set in the
start sections:

  ulimit -s unlimited
  ulimit -n 30000
  ulimit -u 30000

(We'd get alerts long before resource consumption became an issue)

I've been watching the established imap/pop3 connection count on both
directors for the past hour and a half and despite these warnings, those
counts have grown continuously.

The other weird thing is, according the configuration (attached), the ipc
service has a client_limit of 0 by default, so we shouldn't be hitting a
ceiling anyway, correct?

So are these false warnings or something to be concerned about?

-- 
 Tom Pawlowski
 OIT-CSS System Administrator           office: Hill 147
 email: tompru at jla.rutgers.edu          phone:  (732) 445-2634
-------------- next part --------------
# 2.0.14: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.18-194.32.1.el5 x86_64 CentOS release 5.5 (Final) 
auth_anonymous_username = anonymous
auth_cache_negative_ttl = 1 hours
auth_cache_size = 0
auth_cache_ttl = 1 hours
auth_debug = no
auth_debug_passwords = no
auth_default_realm = 
auth_failure_delay = 2 secs
auth_first_valid_uid = 500
auth_gssapi_hostname = 
auth_krb5_keytab = 
auth_last_valid_uid = 0
auth_master_user_separator = 
auth_mechanisms = plain
auth_realms = 
auth_socket_path = auth-userdb
auth_ssl_require_client_cert = no
auth_ssl_username_from_cert = no
auth_use_winbind = no
auth_username_chars = abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@
auth_username_format = 
auth_username_translation = 
auth_verbose = no
auth_verbose_passwords = no
auth_winbind_helper_path = /usr/bin/ntlm_auth
auth_worker_max_count = 30
base_dir = /var/run/dovecot
config_cache_size = 1 M
debug_log_path = 
default_client_limit = 1000
default_idle_kill = 60
default_internal_user = dovecot
default_login_user = dovenull
default_process_limit = 100
default_vsz_limit = 256 M
deliver_log_format = msgid=%m: %$
dict_db_config = 
director_doveadm_port = 9091
director_mail_servers = 192.168.160.74 192.168.160.75 192.168.160.76 192.168.160.77 192.168.160.78 192.168.160.79
director_servers = 192.168.160.80 192.168.160.81
director_user_expire = 15 mins
disable_plaintext_auth = yes
dotlock_use_excl = yes
doveadm_allowed_commands = 
doveadm_password = 
doveadm_proxy_port = 0
doveadm_socket_path = doveadm-server
doveadm_worker_count = 0
first_valid_gid = 1
first_valid_uid = 500
hostname = 
imap_capability = 
imap_client_workarounds = 
imap_id_log = 
imap_id_send = 
imap_idle_notify_interval = 2 mins
imap_logout_format = bytes=%i/%o
imap_max_line_length = 64 k
import_environment = TZ LISTEN_PID LISTEN_FDS
info_log_path = 
last_valid_gid = 0
last_valid_uid = 0
lda_mailbox_autocreate = no
lda_mailbox_autosubscribe = no
lda_original_recipient_header = 
libexec_dir = /usr/libexec/dovecot
listen = *
lmtp_proxy = no
lmtp_save_to_detail_mailbox = no
lock_method = fcntl
log_path = syslog
log_timestamp = "%b %d %H:%M:%S "
login_access_sockets = 
login_greeting = Dovecot ready.
login_log_format = %$: %s
login_log_format_elements = user=<%u> method=%m rip=%r lip=%l mpid=%e %c
login_trusted_networks = 
mail_access_groups = 
mail_attachment_dir = 
mail_attachment_fs = sis posix
mail_attachment_hash = %{sha1}
mail_attachment_min_size = 128 k
mail_cache_fields = flags
mail_cache_min_mail_count = 0
mail_chroot = 
mail_debug = no
mail_fsync = optimized
mail_full_filesystem_access = no
mail_gid = 
mail_home = 
mail_location = 
mail_log_prefix = "%s(%u): "
mail_max_keyword_length = 50
mail_max_lock_timeout = 0
mail_max_userip_connections = 10
mail_never_cache_fields = imap.envelope
mail_nfs_index = no
mail_nfs_storage = no
mail_plugin_dir = /usr/lib64/dovecot
mail_plugins = 
mail_privileged_group = 
mail_save_crlf = no
mail_temp_dir = /tmp
mail_uid = 
mailbox_idle_check_interval = 30 secs
mailbox_list_index_disable = no
maildir_copy_with_hardlinks = yes
maildir_stat_dirs = no
maildir_very_dirty_syncs = no
master_user_separator = 
mbox_dirty_syncs = yes
mbox_dotlock_change_timeout = 2 mins
mbox_lazy_writes = yes
mbox_lock_timeout = 5 mins
mbox_min_index_size = 0
mbox_read_locks = fcntl
mbox_very_dirty_syncs = no
mbox_write_locks = dotlock fcntl
mdbox_preallocate_space = no
mdbox_rotate_interval = 0
mdbox_rotate_size = 2 M
mmap_disable = no
passdb {
  args = proxy=y nopassword=y
  deny = no
  driver = static
  master = no
  pass = no
}
pop3_client_workarounds = 
pop3_enable_last = no
pop3_fast_size_lookups = no
pop3_lock_session = no
pop3_logout_format = top=%t/%p, retr=%r/%b, del=%d/%m, size=%s
pop3_no_flag_updates = no
pop3_reuse_xuidl = no
pop3_save_uidl = no
pop3_uidl_format = %08Xu%08Xv
postmaster_address = 
protocols = imap pop3 lmtp
quota_full_tempfail = no
recipient_delimiter = +
rejection_reason = Your message to <%t> was automatically rejected:%n%r
rejection_subject = Rejected: %s
sendmail_path = /usr/sbin/sendmail
service anvil {
  chroot = empty
  client_limit = 16321
  drop_priv_before_exec = no
  executable = anvil
  extra_groups = 
  group = 
  idle_kill = 4294967295 secs
  privileged_group = 
  process_limit = 1
  process_min_avail = 1
  protocol = 
  service_count = 0
  type = anvil
  unix_listener anvil-auth-penalty {
    group = 
    mode = 0600
    user = 
  }
  unix_listener anvil {
    group = 
    mode = 0600
    user = 
  }
  user = $default_internal_user
  vsz_limit = 18446744073709551615 B
}
service auth-worker {
  chroot = 
  client_limit = 1
  drop_priv_before_exec = no
  executable = auth -w
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 0
  process_min_avail = 0
  protocol = 
  service_count = 1
  type = 
  unix_listener auth-worker {
    group = 
    mode = 0600
    user = $default_internal_user
  }
  user = 
  vsz_limit = 18446744073709551615 B
}
service auth {
  chroot = 
  client_limit = 18466
  drop_priv_before_exec = no
  executable = auth
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 1
  process_min_avail = 0
  protocol = 
  service_count = 0
  type = 
  unix_listener auth-client {
    group = 
    mode = 0600
    user = 
  }
  unix_listener auth-login {
    group = 
    mode = 0600
    user = $default_internal_user
  }
  unix_listener auth-master {
    group = 
    mode = 0600
    user = 
  }
  unix_listener auth-userdb {
    group = 
    mode = 0600
    user = 
  }
  unix_listener login/login {
    group = 
    mode = 0666
    user = 
  }
  user = $default_internal_user
  vsz_limit = 18446744073709551615 B
}
service config {
  chroot = 
  client_limit = 0
  drop_priv_before_exec = no
  executable = config
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 0
  process_min_avail = 0
  protocol = 
  service_count = 0
  type = config
  unix_listener config {
    group = 
    mode = 0600
    user = 
  }
  user = 
  vsz_limit = 18446744073709551615 B
}
service dict {
  chroot = 
  client_limit = 1
  drop_priv_before_exec = no
  executable = dict
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 0
  process_min_avail = 0
  protocol = 
  service_count = 0
  type = 
  unix_listener dict {
    group = 
    mode = 0600
    user = 
  }
  user = $default_internal_user
  vsz_limit = 18446744073709551615 B
}
service director {
  chroot = 
  client_limit = 0
  drop_priv_before_exec = no
  executable = director
  extra_groups = 
  fifo_listener login/proxy-notify {
    group = 
    mode = 0666
    user = 
  }
  group = 
  idle_kill = 4294967295 secs
  inet_listener {
    address = 
    port = 9090
    ssl = no
  }
  privileged_group = 
  process_limit = 1
  process_min_avail = 0
  protocol = 
  service_count = 0
  type = 
  unix_listener director-admin {
    group = 
    mode = 0600
    user = 
  }
  unix_listener director-userdb {
    group = 
    mode = 0600
    user = 
  }
  unix_listener login/director {
    group = 
    mode = 0666
    user = 
  }
  user = $default_internal_user
  vsz_limit = 18446744073709551615 B
}
service dns_client {
  chroot = 
  client_limit = 1
  drop_priv_before_exec = no
  executable = dns-client
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 0
  process_min_avail = 0
  protocol = 
  service_count = 0
  type = 
  unix_listener dns-client {
    group = 
    mode = 0666
    user = 
  }
  unix_listener login/dns-client {
    group = 
    mode = 0666
    user = 
  }
  user = $default_internal_user
  vsz_limit = 18446744073709551615 B
}
service doveadm {
  chroot = 
  client_limit = 1
  drop_priv_before_exec = no
  executable = doveadm-server
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 0
  process_min_avail = 0
  protocol = 
  service_count = 1
  type = 
  unix_listener doveadm-server {
    group = 
    mode = 0600
    user = 
  }
  user = 
  vsz_limit = 18446744073709551615 B
}
service imap-login {
  chroot = login
  client_limit = 0
  drop_priv_before_exec = no
  executable = imap-login director
  extra_groups = 
  group = 
  idle_kill = 0
  inet_listener imap {
    address = 
    port = 143
    ssl = no
  }
  inet_listener imaps {
    address = 
    port = 993
    ssl = yes
  }
  privileged_group = 
  process_limit = 12222
  process_min_avail = 10
  protocol = imap
  service_count = 1
  type = login
  user = $default_login_user
  vsz_limit = 2 G
}
service imap {
  chroot = 
  client_limit = 1
  drop_priv_before_exec = no
  executable = imap
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 1024
  process_min_avail = 0
  protocol = imap
  service_count = 1
  type = 
  unix_listener login/imap {
    group = 
    mode = 0666
    user = 
  }
  user = 
  vsz_limit = 18446744073709551615 B
}
service ipc {
  chroot = empty
  client_limit = 0
  drop_priv_before_exec = no
  executable = ipc
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 1
  process_min_avail = 0
  protocol = 
  service_count = 0
  type = 
  unix_listener ipc {
    group = 
    mode = 0600
    user = 
  }
  unix_listener login/ipc-proxy {
    group = 
    mode = 0600
    user = $default_login_user
  }
  user = $default_internal_user
  vsz_limit = 18446744073709551615 B
}
service lmtp {
  chroot = 
  client_limit = 0
  drop_priv_before_exec = no
  executable = lmtp
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 0
  process_min_avail = 0
  protocol = lmtp
  service_count = 0
  type = 
  unix_listener lmtp {
    group = 
    mode = 0666
    user = 
  }
  user = 
  vsz_limit = 0
}
service log {
  chroot = 
  client_limit = 0
  drop_priv_before_exec = no
  executable = log
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 1
  process_min_avail = 0
  protocol = 
  service_count = 0
  type = log
  user = 
  vsz_limit = 18446744073709551615 B
}
service pop3-login {
  chroot = login
  client_limit = 0
  drop_priv_before_exec = no
  executable = pop3-login director
  extra_groups = 
  group = 
  idle_kill = 0
  inet_listener pop3 {
    address = 
    port = 110
    ssl = no
  }
  inet_listener pop3s {
    address = 
    port = 995
    ssl = yes
  }
  privileged_group = 
  process_limit = 4096
  process_min_avail = 0
  protocol = pop3
  service_count = 1
  type = login
  user = $default_login_user
  vsz_limit = 64 M
}
service pop3 {
  chroot = 
  client_limit = 1
  drop_priv_before_exec = no
  executable = pop3
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 1024
  process_min_avail = 0
  protocol = pop3
  service_count = 1
  type = 
  unix_listener login/pop3 {
    group = 
    mode = 0666
    user = 
  }
  user = 
  vsz_limit = 18446744073709551615 B
}
service ssl-params {
  chroot = 
  client_limit = 0
  drop_priv_before_exec = no
  executable = ssl-params
  extra_groups = 
  group = 
  idle_kill = 0
  privileged_group = 
  process_limit = 0
  process_min_avail = 0
  protocol = 
  service_count = 0
  type = startup
  unix_listener login/ssl-params {
    group = 
    mode = 0666
    user = 
  }
  user = 
  vsz_limit = 18446744073709551615 B
}
shutdown_clients = yes
ssl = required
ssl_ca = </usr/local/certs/SSLWebServerCABundle.txt
ssl_cert = </usr/local/certs/imapd-pop3d.pem
ssl_cert_username_field = commonName
ssl_cipher_list = HIGH:MEDIUM:+SSLv3:!SSLv2
ssl_key = </usr/local/certs/imapd-pop3d.pem
ssl_key_password = 
ssl_parameters_regenerate = 168
ssl_verify_client_cert = no
submission_host = 
syslog_facility = mail
userdb {
  args = 
  driver = passwd
}
valid_chroot_dirs = 
verbose_auth = no
verbose_proctitle = no
verbose_ssl = no
version_ignore = no
protocol imap {
  mail_max_userip_connections = 10
}
protocol pop3 {
  mail_max_userip_connections = 5
}


More information about the dovecot mailing list