MAIL_DRIVER=smtp
MAIL_HOST=smtp.mydomain.eu
MAIL_PORT=25
MAIL_USERNAME=null
MAIL_PASSWORD=null
MAIL_ENCRYPTION=null

#25 smtp (TCP)
#110 pop3 (TCP)
#143 imap (TCP)

#465 smtps (TCP)
#993 imaps (TCP)
#995 pop3s (TCP)

AND

#587 mail message submission (TCP)