Thunderbird able to send mails despite no SMTP is configured

[My287thNick]

Dear experts,

I want that it is not possible to send mails from a specific mail account in thunderbird, so I deleted the account's SMTP server in the account settings. However, it changed nothing. Also not after restarting. When I click new mail, there is still the respective mail address in the "from" field and sending it works flawlessly - which shouldn't be in this case. I wonder, where thunderbird has the credentials needed to send the mail, since I deleted the SMTP server?

Anybody has some idea?

Thanks!

[DanRaisch]

Do you have more than one account set up in that installation of Thunderbird?
Have you checked the Server Settings after restarting Thunderbird to ensure that the unwanted SMTP definition is no longer listed?

[makaiguy]

In the Account Settings page for that account (not its subsidiary Server Settings page), check at the bottom of the page to see what you have listed as the SMTP server. Perhaps it is set to use a different SMTP server than the one you deleted.

As for the email address showing in the From field, that is defined on that same Account Settings page, independent of any SMTP settings.

[My287thNick]

Many thanks for your answers! You are right. I did not realize that the smtp server of the accounts default entity jumped to default smtp server after deleting its respective smtp server. So mails got send over that other, default smtp server. I did not know that one can simply send an email from the account "foo@a.com" over the smtp server from the mail account "foo@b.com" without any error message. i just found out via inspecting the source code/headers of such an email sent from another smtp. There, the actual smtp server showed up in the "received" header.

I wonder why there is no option do simply disable sending mails for a specific account in TB. However, I now created a "blah" smtp server and set it on that account and thus, mails cannot be sent by that account erroneously any more - which is exactly what I want.

Thanks!