On February 20, 2026 3:40:59 AM GMT+02:00, Steve Litt via dovecot <dovecot@dovecot.org> wrote:

Hi all,

I have Dovecot 2.4.2 working (plain text only) on my Qemu virtual machine, with Claws-Mail able to work with all its files. However, I want to declare the Dovecot server as running on Port 143, and when I do, I dovecot -F throws the error message shown later in this message. If I comment out the explicit port declaration, it works fine, and I want to know why. To the best of my knowledge, my declaration of port 143 exactly matches your 2.4.2 documentation:

The following is my attempt to tell Dovecot to serve *explicitly* at port 143:

===============================================

My Dovecot server will operate on Localhost

listen = 127.0.0.1

service imap { inet_listener imap-login { port = 143 }

inet_listener imaps {

port = 993

ssl = yes

}

}

The following is the result:

=============================================== [root@dovecotvoid ~]# dovecot -F doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf: duplicate listener: 143:127.0.0.1 [root@dovecotvoid ~]#

If I comment out the port = 143, it works. Why is it griping about a duplicate listener? At the bottom of this email is the entire dovecot.conf and the result of dovecot -n, and there are no sub-configuration files in conf.d :

===============================================

Start new configs with the latest Dovecot version numbers here:

dovecot_config_version = 2.4.2 # Must be current version dovecot_storage_version = 2.4.2 # Must be current version or earlier # 2.3 is minimum

I only want imap

protocols { imap = yes lmtp = no pop3 = no }

My Dovecot server will operate on Localhost

listen = 127.0.0.1

service imap { inet_listener imap-login { port = 143 }

inet_listener imaps {

port = 993

ssl = yes

}

}

mail_home is only for virtual users

A virtual user is a user with no system account

I have no virtual users, so I've commented out mail_home.

#mail_home = /srv/mail/%{user}

mail_driver is the storage format

mail_driver = maildir

mail_path is location of top of storage data

WARNING: For troubleshooting be prepared to switch

to literal location of ~

mail_path = ~/mail/Maildir # In my case

mail_home is the home directory of the user identified as ~

WARNING: system users have no ~ without it.

mail_home = /home/slitt

You need a log you can locate

There might not be a

log_path=/var/log/dovecot.log

#mail_uid = slitt #mail_gid = slitt mail_uid = vmail mail_gid = vmail

By default first_valid_uid is 500.

#If your vmail user's UID is smaller,

you need to modify this:

#first_valid_uid = uid-number-of-vmail-user

namespace inbox { inbox = yes separator = / }

Authenticate as system users:

passdb pam { driver = pam #driver = passwd }

userdb passwd { driver = passwd }

#ssl_server_cert_file = /etc/dovecot/ssl-cert.pem #ssl_server_key_file = /etc/dovecot/ssl-key.pem

The following is the output of dovecot -n:

===============================================

2.4.2 (0962ed2104): /etc/dovecot/dovecot.conf

OS: Linux 6.12.71_1 x86_64

Hostname: dovecotvoid

dovecot_config_version = 2.4.2 dovecot_storage_version = 2.4.2 listen = 127.0.0.1 log_path = /var/log/dovecot.log mail_driver = maildir mail_gid = vmail mail_home = /home/slitt mail_path = ~/mail/Maildir mail_uid = vmail protocols { imap = yes lmtp = no pop3 = no } service imap { inet_listener imap-login { port = 143 } } namespace inbox { inbox = yes separator = / } passdb pam { driver = pam } userdb passwd { driver = passwd }

===============================================

---

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This is because of service imap-login. It already has listener for port 143. Adding it to service imap directly won't work.

See doveconf service/imap-login

Aki