[Dovecot] systemd socket and service

Hello. I'm use systemd and have some questions:

1. Why dovecot.socket contains only imap ListenStream? [Unit] Description=Dovecot IMAP/POP3 email server activation socket

[Socket] #dovecot expects separate IPv4 and IPv6 sockets BindIPv6Only=ipv6-only ListenStream=0.0.0.0:143 ListenStream=[::]:143 ListenStream=0.0.0.0:993 ListenStream=[::]:993 KeepAlive=true

2. Does dovecot.service required to use dovecot lmtp, or it may be stoppped (i not often check my mails via client, but have many incoming mails some time)

-- Vasiliy G Tolstov <v.tolstov@selfip.ru> Selfip.Ru