If you send marketing emails you are more than likely familiar with the many blocklists in use today. One thing to keep in mind when you find yourself on one of these lists is that most lists will contain just about any email marketer at one point in time or another. At the end of the day, if you are sending promotional mail, you’ll want to pay attention to any blacklistings that may arise, but must quantify taking action against these listings based on the impact to your own deliverability.
Any listing is indicative of a systemic issue: list hygiene. If you find yourself blacklisted, you may simply be mailing promotional mail to your own subscriber base, mailing to an unengaged audience or not setting proper expectations with your customers. Most blacklistings will have minimal impact on deliverability (outside of a Spamhaus listing), but all are a red flag and should be monitored regularly.
While we regularly monitor all of our sending domains and IP addresses to ensure that we are aware of and may address any critical blacklistings, the Cordial Deliverability Operations team recommends that you also regularly check any domains/IP addresses that you have in use against private and public blocklists.
Below are a few of the more common blocklist checkers available, as well as a list of the most common blocklists in use today.
|The Anti-Abuse Project||anti-abuse.org/multi-rbl-check|
|SORBS (Spam and Open Relay Blocking System)||sorbs.net|
|SBL (SpamHaus Blocklist)||spamhaus.org/sbl/|
|PBL (Spamhaus Policy Block List)||spamhaus.org/pbl/|
|CBL (Composite Blacklist), a division of Spamhaus||cbl.abuseat.org|
Top 2 Blocklist Owners That Cordial Monitors
The most common blocklist owners that the Deliverability Operations team may come across while monitoring here at Cordial are:
Spamhaus is the most highly visible blocklist owner active today and will impact one’s mailing capabilities greatly. 70-80% of all mail sent by those who find themselves blacklisted by Spamhaus, will be blocked by the ISPs/MBPs utilizing these blocklists. A detailed outline of the various lists may be found below.
|SBL||Spamhaus Block List||IP Address||spamhaus.org/sbl|
|XBL||Exploits Block List||IP, exploited computers and other devices||spamhaus.org/xbl|
|PBL||Policy Block List||IP Address Ranges||spamhaus.org/pbl|
|DBL||Domain Block List||Domain||spamhaus.org/dbl|
|CBL||Composite Blocking List (a division of Spamhaus)||IP Address - Easy removal||abuseat.org|
SORBS is another commonly found blocklist owner. We have found that the impact to any mailing program is minimal, especially compared to a listing by Spamhaus.
SORBS (Spam and Open Relay Blocking System) is a DNS-based Block List (DNSBL) that is reported as a way for MBP/ISPs to disseminate the various forms of malicious email. The list typically includes email servers suspected of sending or relaying spam, hijacked servers or those with Trojan infestations.
|SORBS||Spam and Open Relay Blocking System||DNS||sorbs.net|