You can use telnet at port 25 and use via normal smtp protocal, or use helper script like
bash tests/smpt.bash
# test authentication
doveadm auth test [email protected]
# show informations about the user (user attributes)
doveadm user -u [email protected]
# show quota for a specific user
doveadm quota get -u [email protected]
# see all received emails
doveadm fetch -u [email protected] "text" ALL
password=supersecret
mysql -u root -p$password -e "select * from mailserver.virtual_domains"
mysql -u root -p$password -e "select * from mailserver.virtual_users"
mysql -u root -p$password -e "select * from mailserver.virtual_aliases"
To see only postfix non default config values
postconf -n
To see only dovecot non default config values
doveconf -n
/var/log/mail.log
/var/log/dovecot.log
dovecot writes logs here as well
/var/log/auth.log