Re: [swinog] Handling of UCE / RBL while minor misconfigurations

Mail server admin can do a SPF check (or have a list of allowed source email domains) before outbound and reject forwarding these emails.

You can check this before you allow the domain to be sent. However, I don't know of any mail server/MTA that can do this out-of-the-box. And note also:

1. You would have to do this before sending every single email, because DNS records can change. As a mail server provider you have no control over it. 2. Even then it can take a while until you as a sender server notice this, thanks to TTL and DNS propagation. 3. The way this (to us unknown provider) works, you can't technically handle the problem (siehe 1. und 2.)