Is it possible to have an SMTP login without a username, but with a password?

Question

Sometimes, users of our software, which connects to SMTP servers, put in a password, but no username. (Or, rather, their browsers' autocomplete specifies a password, but no username.)

Is there any valid SMTP configuration that has a password and no username? Are we safe in ignoring any password when there is no username?

Answer 1

Is there any valid SMTP configuration that has a password and no username?

No. Theoretically, someone could code up an SMTP server that allowed this for some wacky reason, but I'm not aware of it existing.

Are we safe in ignoring any password when there is no username?

Yes.

Good luck,

--jed