On 28 Oct 2022, at 14:40, Piperみかこ wrote: > Hello,
Hey, > What's the difference between these two options? > > smtp_use_tls > smtpd_use_tls > > Does the second one mean submission? Nope. smtp_(*) options are used when postfix acts as an SMTP client, whereas smtpd_(*) options are when it serves as receiving incoming emails from remote servers. > And, for an incoming message, how postfix knows the behavior is made by a > peer MTA, or by a remote smtp client (like thunderbird)? Because both MTA > and thunderbird can use port 25 for sending. Port TCP/25 should only be used for SMTP servers (ie. relaying emails) and not for users submitting emails (whose should use submission’s port (TCP/587) or smtp’s port (TCP/465). > I am a bit confused. To clarify things, postfix is and acts as a: - MTA when it relays emails to remote SMTP servers to deliver (acting as SMTPD when receiving incoming flows and SMTP client when relaying flows to remote SMTPD servers); - MSA when authenticated users submit emails whose should be relayed to recipient(s). hth -- matt [at] lv223.org GPG key ID: 7D91A8CA
signature.asc
Description: OpenPGP digital signature
