RHS Blacklists

Our anti-spam system uses RHSBLs (Right Hand Side Black Lists) to block email from spammers.

An RHSBL is a list that keeps track of domains, rather than IP addresses. The term "right hand side" comes from the fact that it looks for the domain name in an email address, which is on the "right hand" side of the @ sign. Spammers often change their IP addresses, so this can be a good way to keep track of them.

You have the ability to change the RHSBLs that currently affect your email.

RHS Blacklists


This is an RHSBL that lists domains that send pornographic emails.

Using this list will attempt to block remote senders who are using domains that are sending pornographic emails.


This is an RHSBL that lists domains that send bulk email, unconfirmed mailing-lists, and unsolicited advertising.

Using this list blocks a lot of questionable email. Specifically, it blocks:

Unsolicited Advertising
Sites that have purchased or aquired lists of email addresses from third parties and send advertisments in bulk.
Unconfirmed Mailing-lists
Mailing-lists that do not send initial messages for users to confirm that they want to be on the list.
Bulk Email
Any other types of email sent to large, unsolicited lists.

Many of these domains are email marketing companies that can send out legitimate email as well as spam. If you use this list, you may be prevented from receiving promotions from these companies, even if you sign up for them.


This is an RHSBL that contains domains that were set up, or have been used, to host misleading, "phishing" or otherwise fraudulent webpages.

Using this list blocks a lot of fraudulent email. Many con-artists set up websites that resemble legitimate sites that you normally would log into (e.g. eBay, PayPal, etc.). They then get your login and password information and use it to steal from you. This activitiy is called "Phishing". This list blocks domains that have been caught Phishing, or otherwise engaged in illegal or deceptive behavior.


This is an RHSBL that contains a list of domains that are owned and/or operated by known spammers.

AHBL keeps track of abusive hosts. This is the RHSBL counterpart to their DNSBL. These domains are known spammers, so it's unlikey that it will block legitimate email.