Dealing with Blacklists & Reputation Issues

One of, if not the most typical, reasons emails do not deliver is they are on a blacklist. There are hundreds of publicly available blacklists out there, and depending how you do email marketing, you can get listed on them at any time.

You should always keep an eye on your IP and domain reputation making sure you spot issues quickly and react to them.  It is important to note, that being on a blacklist does not mean all your emails will be blocked.  Not all blacklists are equal and who monitors a blacklist will change all around the world. 

Blacklists can also exist privately and affect only the users within that blacklist network. For example, being blacklisted by Barracuda will only matter for users of Barracuda.  Microsoft won't pick up on it and inherit the blacklist too.  But being blacklisted at Spamhaus could be inherited by Barracuda and Microsoft.  

What is a Blacklist?

There are two types of blacklists: IP based and domain based.  

When you send an email it comes from both a domain and an IP.  At CommuniGator you are allocated a dedicated IP address that no other customer uses, but all your domains will use the same IP. This means an IP blacklist will affect all your email marketing because it wont matter what domain you use.

If the worst happens and you do get blacklisted, we will always attempt to resolve it for you first.  Some de-lists occur automatically after a period of time, others need manual requests, but then automatically pass, while the rest need manual requests that a human will consider before removal.  Repeat offenses can make future de-lists more complicated. 

The table below covers some of the top blacklists that you may come across:

Blacklist Name Description Block Type Duration Severity De-list Process URL
AOL
 One of the major ISPs and depending how much of your audience is AOL based a blacklist is not good. Listings are typically triggered from sending behavior.  Such as too many complaints, too much bad data, and spam traps.  
 IP Permanent until requested, then days or weeks.
 High De-listing must be submitted on their website and can be challenging to resolve.
 Link
ATT Block
 A blacklist only used for att.net email addresses.  Severity dependent on target audience because of this. It is not known what triggers a listing but it is probably user complaints.
 IP Permanent until requested, then 1-2 days.
 Low De-listing seem to auto expire but they do have a contact method to a delist manually.
 Link
Barracuda
 A widespread blacklist.  Barracuda provide anti-spam for 1000s of companies around the world. User complaints are the primary trigger to become listed.  
 IP & Domain
 Permanent until requested, then within 24 hours.
 High De-lists are automated after submitting on their website.  
 Link
CBL A medium spread blacklist that mainly trigger from spamtraps.   IP Unknown
 Medium De-lists are usually automated but sometimes more information is requested.  
 Link
Fortiguard
 A widespread blacklist.  Fortiguard provide anti-spam for 1000s of companies around the world. It is not known what triggers a listing.  
 IP Unknown Low De-list requests must be submitted on their site or emailed in.  
 Link
GMAIL
 One of the major ISPs and so a blacklist here is not good.  Severity dependant on target audience because of this. Listings are typically triggered from sending behaviour.  Such as too many complaints, too much bad data, and spam traps.  
 IP & Domain
 Permanent until requested, then days or weeks.
 High De-listing must be submitted on their website and can be very challenging.  In our experience when a listing is in place, the actual sending customer must be the one to do it.
 Link
Hotmail SNDS / Outlook . com
 One of the major ISPs and so a blacklist here is not good.  Severity dependant on target audience because of this. Listings are typically triggered from sending behaviour.  Such as too many complaints, too much bad data, and spam traps.  
 IP
 Permanent until requested, then 1-2 days.
 High
 De-listing must be submitted on their website.  All requests return an automated response that if it confirms if the request was accepted or not.  If this email is replied to it will then be reviewed by someone.
 Link
messaging . microsof t .com
 A blacklist only used for messaging.microsoft.com email addresses.  
 IP Permanent until requested, then 1-2 days.
 Medium De-listing must be emailed to them explaining why you should be.
 Link
Office 365
 A widespread blacklist as Office 365 is used by 1000s of companies around the world. It is not known what triggers a listing.  
 IP Permanent until requested, then immediate.
 High De-list requests must be submitted on their site but the good news is all requests are automatic.  Submit a de-list using the online form.  In the received email click the link.  The IP should be auto de-listed shortly after.
 Link
ProofPoint
 A widespread blacklist as Proofpoint provide anti-spam services for 1000s of companies around the world. Severity is dependent on the target audience because of this. It is not known what causes a listing.  
 IP Temporary Medium IPs are typically only listed for a short amount of time, and are removed automatically after their triggers (maybe complaints) cease.  If however an IP is listed at the time you check, you must submit a delist on the site.  
 Link
SpamCop A hugely widespread blacklist.  A listing here affects 1000s of companies around the world. Listings are typically triggered from sending behaviour.  Such as hitting spam traps or generating user complaints.  
 IP 24 hours minimum High  If the IP has never been listed before, you can get an almost instant de-list (express de-list) by using their website and submitting. De-lists are automatic and they tell you how long that will be on the site. It starts at 24 hours from the initial listing, and the time is reset if further spam traps or complaints come in.   The only way to avoid a listing is to not send to bad data. For spamtraps, as the listing could be caused by any one address within 100,000s of emails, the only way to narrow the bad data down is to half campaign audiences, sending to each half days apart, and see if the listing comes back.  If its complaints you can’t do anything except typical actions to try and not make people report received emails to Spamcop.
 Link
URIBL
 It is not known how widespread these are anymore or what causes a listing. They used to be very influential but that has changed over the last few years.  Listings were complaint driven and a de-list was usually rejected without some grovelling. Now it seems a listing will auto expire after an unknown time has passed, or a de-list request on their website is accepted without much hassle.
 Domain Temporary Medium Request a de-list via the online form and check the outcome. They can be accepted quite quick, or sometimes rejected with minimal explanation. Should one get denied you must re-submit and be very thorough explaining why you are challenging their denial.
 Link
Yahoo One of the major ISPs and so a blacklist here is not good.  Severity dependent on target audience because of this. Listings are triggered from sending behaviour.  Usually emails are accepted for a time, then based on complaints delivery attempts start getting transient denied with messages saying "temporarily deferred due to too many complaints, please try again later". If complaints cease, normal email behaviour is resumed.  If complaints persist, the transient denial will persist too.  If it gets severe enough the transient denials will change to immediate bounce rejections.  De-lists however are automatic if the denial doesn’t get to the severe state.  When the email activity stops because the campaign is over, the next send will start from the beginning again.  Getting delivered to Yahoo is a case of sending small campaigns spread out, instead of large campaigns or many small ones at the same time.  
 IP Temporary to several days High If the blacklist doesn’t disappear then you must request a de-list on their website.
 Link