参考下面的配置，pop3同理：

/etc/dovecot/conf.d/10-master.conf

service imap-login {
  inet_listener imap {
    #port = 143
  }
  inet_listener imap_9143 {
    port = 9143
  }
  inet_listener imap_whatever {
    port = 54321
  }
}