Learn how to blacklist an email address in the Account Control Center:
Hi. Sean here. We're talking about blocking bad senders or blacklisting a sender.
Typically, you're doing this because you're getting junk mail from a particular address that shows up often.
And so what you want to do when you get into the ACC, you click on E-Mail and then Manage Junk E-mail Filter Settings, scroll down to the bottom here where it says Add, Remove, or View Rejected Addresses and Add Rejected Addresses and you have a little text field to add in your address.
Now, the natural tendency, here, is to take the address that shows up in the message in the From header. In this case, I have an example message here and the from header shows up as email@example.com. However, where you want to get this address from is the return path header.
To see the return path header we have to view the full message headers and in Roundcube, you go up here, click on More, Show Source, and it shows you the full message headers. And here it is, right at the top here: the return path header. That's what we're after and it shows the true sender of that is firstname.lastname@example.org and that's the true sender of this
message and that's the address you want to block.
So we take that copy it, go back over to the ACC, paste it in, maybe add in some comments here like, “bad spammer” and then we click Add Rejected Addresses.
So the next time email@example.com sends you a piece of junk mail since she's listed here in your blacklisted addresses, it gets blocked at the SMTP time and doesn't even get accepted by a server.
That's all there is to it. If you have any questions check out kb.pair.com or email us at firstname.lastname@example.org. Have a great day.