In our low-traffic server we have always kept the default value for IMAP mail_max_userip_connections (10).

The server has been working fine! (Thank you Timo for this!)

However, recently we have been having:

Maximum number of connections from user+IP exceeded

errors both for IMAP and webmail users.

Thus, we have now changed the value to 100.

The questions:

1.Might this lead to overloading the server? 2. Could another dovecot setting prevent the above setting from being applied (e.g. due to connections exhaustion), i.e. should we also change other setting(s)? 3. What should we take into account when deciding the value for mail_max_userip_connections? 4. How can we set a different value to this directive for webmail connections (coming from 127.0.0.1, ::1)?

The config follows for your reference (I've only changed the real domain name).

Thanks in advance for your help. Nick

# doveconf -n # 2.2.18: /etc/dovecot/dovecot.conf # Pigeonhole version 0.4.8 # OS: Linux 2.6.18-407.el5 x86_64 CentOS release 5.11 (Final) auth_mechanisms = plain login auth_verbose = yes disable_plaintext_auth = no dsync_remote_cmd = ssh -l root vmail1.example.com doveadm dsync-server -u%u mail_gid = 500 mail_location = maildir:~/Maildir/ mail_plugins = quota mail_log notify replication mail_uid = 500 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 index ihave duplicate passdb { args = /etc/dovecot/dovecot-passdb-ldap.conf driver = ldap } plugin { mail_log_events = delete undelete expunge copy mailbox_delete mailbox_rename mail_log_fields = uid box msgid size mail_replica = remote:vmail@vmail1.example.com quota = maildir:User quota quota_rule = *:storage=5G quota_rule2 = Trash:storage=+3%% quota_warning = storage=75%% quota-warning 75 %u quota_warning2 = storage=90%% quota-warning 90 %u } protocols = imap pop3 service aggregator { fifo_listener replication-notify-fifo { user = vmail } unix_listener replication-notify { user = vmail } } service auth { unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } unix_listener auth-master { group = vmail mode = 0660 user = vmail } user = root } service imap-login { service_count = 1 vsz_limit = 64 M } service imap { executable = imap postlogin } service pop3-login { service_count = 1 vsz_limit = 64 M } service pop3 { executable = pop3 postlogin } service postlogin { executable = script-login -d rawlog } service quota-warning { executable = script /opt/mail1.sh unix_listener quota-warning { user = vmail } user = vmail } service replicator { process_min_avail = 1 unix_listener replicator-doveadm { mode = 0600 } } ssl_ca =