nsumner It seems that opportunistic STARTTLS on port 25 is not enabled. Which means I can’t login with a username and password using STARTTLS to send an email. Is there anyway to change this?
nsumner So I am a little confused. I see that it does allow STARTTLS (which is good). What is being rejected any authentication. What port could I use for authenticated non STARTTLS traffic? I have one piece of equipment that is very limited in what I can choose?
esackbauer nsumner https://docs.mailcow.email/client/client-manual/ If you cannot configure port 587 (which is very bad if your equipment does not support it), and must use port 25, then define the IP address of that host as “Forwarding Host”. You then do not need authentication on port 25.
ETNyx Client -> Server communication should be managed on port in sequence smtp,pop,imap 587,110,143 or 465,995,993 for SSL/TLS (fully encrypted)