DKIM not working when sending via SMTP on port 25 without authentication

DKIM is working fine when I send mail via Virtualmin's web mail interface. Also it works fine when my email application (Thunderbird) is configured to connect via port 465 (TLS, with password).

Only when I configure Thunderbird to use port 25 without authentication, it sends emails without DKIM.

Not sure if this is a bug or a feature.

Of course, this works only when Thunderbird is connecting to port 25 via Socks proxy, created by ssh. The SMTP server will reject messages from "another network".



unborn's picture
Submitted by unborn on Mon, 03/20/2017 - 04:46 Pro Licensee

Hi, I think its standard. In past I was not able to send emails to anything including gmail or other email providers when email send without authentication. Even if I was able to send it, nearly 99.9% of receivers blocked that email because it was send without authentication which is kindly good to prevent some kind of spam.

But It would be great if Virtualmin changes this when installed. Because most users don't expect things to not work simply because they don't use authentication.

Yeah in most cases it would be necessary to authenticate when sending an email.

Does DKIM work properly for you when an email is generated from the server itself, such as using a webmail client?

unborn's picture
Submitted by unborn on Mon, 03/20/2017 - 23:42 Pro Licensee

Hi, yes however I use rainloop as my webmail client - to be honest my girlfriend is using it as she dislikes for some reason thunderbird. Rainloop is basically working as well same as thunderbird.

How are you able to send email via port 25 without authentication though? In the default config, Virtualmin disallows this (or else spammers would be able to relay via your server).