Running Dovecot From Inetd
Preferred way to run Dovecot is to just start the dovecot binary, but it's also possible to run from inetd:
imap stream tcp nowait root /usr/sbin/tcpd /usr/local/libexec/dovecot/imap-login imaps stream tcp nowait root /usr/sbin/tcpd /usr/local/libexec/dovecot/imap-login --ssl pop3 stream tcp nowait root /usr/sbin/tcpd /usr/local/libexec/dovecot/pop3-login pop3s stream tcp nowait root /usr/sbin/tcpd /usr/local/libexec/dovecot/pop3-login --ssl
imap-login and pop3-login automatically start dovecot master process if it's not already running. NOTE: If you change any configuration, Dovecot doesn't notice the change unless the master process is restarted, or if HUP signal is sent to it. This makes Dovecot somewhat special as a inetd-based service.
Running Dovecot From xinetd
sample configuration for imap and imaps
service imap { disable = no socket_type = stream protocol = tcp wait = no user = root server = /usr/local/libexec/dovecot/imap-login flags = IPv4 only_from = 127.0.0.1 banner = /usr/local/etc/deny_banner } service imaps { disable = no socket_type = stream protocol = tcp wait = no user = root server = /usr/local/libexec/dovecot/imap-login flags = IPv4 server_args = --ssl }