Port 465: SMTPS
Port 465 is email submission over TLS, used by mail apps to send messages over an encrypted connection.
What runs on port 465
465 was briefly assigned to SMTP over SSL in the 1990s, then withdrawn, but providers kept using it. In 2018 RFC 8314 formally re-assigned it for mail submission with TLS from the first byte, and it now sits alongside 587, which upgrades with STARTTLS instead.
On a home network
Home devices do not listen on 465. Printers, cameras, NAS boxes and phones sending email alerts connect out to a provider on 465 or 587, which is normal.
If port 465 is reachable from the internet
On a mail provider's server, 465 is meant to be open. At home, nothing should answer on it unless you host email. Exposed submission servers attract password guessing aimed at accounts that can send spam.
How to check whether it is open on your network
If an outside scan shows 465 on your public address, look for a mail server package on a NAS or PC and the port forward that exposes it.
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