client

[localadmin33]

Hello. We use postal as a mail server. Our client is written in Python. But we want to refuse this client. Tell me, is authentication possible in Thunderbird via smtp?
There are 2 server parameters. Incoming mail server with port and outgoing mail server. Is there such a possibility?

[localadmin33]

as well as any other email clients (RoundCube, Rainloop)

[willpower232]

Technically you can use any smtp client for sending messages with Postal however as it doesn't have mailboxes or many of the features of a traditional email server, thunderbird might get upset that it has nothing to receive with.

Regarding blocking specific clients, unfortunately that isn't really possible as clients don't tend to identify themselves, at least it isn't really part of any standard I am aware of. You would probably do better with just disabling the SMTP credential you are using and start a new one.