I have added some domains, not email addresses, to my blacklist, but it does not seem to be blocking my choices.

What is the proper syntax?

I want to block a couple of domains. is it *@comcast.com , comcast.com, *.comcast.com or what?

Can you also block IPs?

Thanks

comcast.com is the correct format

According to the instructions the personal blacklist uses the Return-Path field. How do I blacklist messages with "<>" as the Return-Path? I'm getting several of these a day.

Hmmm... I was told that blacklist actually resolve the source and then blacklist from there. Was I told incorrectly?

There are 2 different blacklists at work here.

The one being discussed here is the personal blacklist available in webmail (along with a personal whitelist) and those only work with the email address of the sender. I was under the impression that both the From and Return-Path fields were used in looking for a match, but cats is correct that the description does mention that only the Return-Path is used. There have been requests to expand the capabilities of the personal white/black lists to include other fields, but they have not been implemented as of yet.

A standard DNS Blacklist like spamcop does indeed look at the IP address of the sending server to determine if it is blocked.

In this way, a person can receive messages they want from a DNS blacklisted server by using their whitelist. For instance, the only SMTP server for foo.com is on the spamcop blacklist. You have a friend who uses foo.com for their ISP. You whitelist the address user<at>foo.com and any message except from your fried will be blocked. If you whitelist foo.com entirely, the spamcop blocklist for that server is over ridden.