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emails being blocked - SPAM blacklists


There are several hundred SPAM blacklists but there are a few tools that can help you check most of them quickly. Here a handy reference with the sites that you can use to check your blacklist status. We've also highlighted one or two of the more prominent SPAM blacklists.

Please Note: we provide this information as a courtesy.

What you need to know to check Blacklist status:

Some SPAM blacklists track more than IPs they also track domains, URLs and a few even create a unique hash code based on the content of the email. If their systems see more than a few dozen emails with an identical code meaning dozens (or more) of identical emails, they will list the specific email content as SPAM.

You can check multiple public blacklists if you know your servers IP address(es): MXToolbox is free.

  1. google 'whats my IP address'. this will give you the IP address of your internet connection
  2. go to and enter your IP addres
  3. enter you IP addresses and MXToolbox checks about 100 blacklists
  4. if you are blacklisted take the following steps below

IMPORTANT: You must clean all machines and devices for Trojans and viruses BEFORE applying to be unlisted. If you end up on a blacklist again its hard to be unlisted. We recommend AVG for virus checking and MALEWARE TOOLS to scan for Trojans etc. These seem to pickup more malicious files then most.


A few blacklists deserve special mention: (
One of the most widely used blacklists, SPAMHaus.orgs mission is to rid the world of unsolicited commercial email (UCE) by creating and monitoring a network of millions of spam honey-pot email addresses. These are email addresses that are expired, or that never were real recipients that Spamhaus acquires from ISPs. They re-purpose expired domains and rumor has it also plant addresses on various websites around Etherspace. Since these are not real people the addresses should never end up on an opt-in list, so if you send an email campaign and it ends up in one of Spamhaus inboxes clearly your list development practices are not cool. [Note: Some list vendors develop emails lists - albeit illegally - by scraping websites for email addresses. This is why you should never us these lists].

Spamhaus then adds the sending email servers to their blacklists. Overall its a pretty good system but not flawless in our experience. For example, if you are capturing registrant information from your website or from online events, an ill-willed smart-alec can enter a bogus / honey-pot address into your list. Your well intentioned campaign gets caught and viola you are on Spamahaus [s]hit list. Solution: Always use double opt-in processing (most email services providers like Pinpointe provide mechanisms to enforce double opt-in when using their forms to collect subscribers).

UCEProtect (
UCE Protect deserves mention because its one of the few major SPAM blacklists where you can blacklisted because of something someone else did. UCEProtect monitors and tracks the SPAM reputation of individual email server IP addresses, and factors in the reputation of other servers in the same network as well as servers hosted by the same ISP.

UCEProtects guilt by association approach means your servers can be blacklisted if your ISP hosts other systems that are caught for SPAMming.

Heres an example. Your companys servers are hosted with (we made that up just on case you werent sure). Now, assume hosts hundreds of thousands of companies and has 30,000 IPs under management, including your one, lonely email server. One day, a SPAMMER who is a customer of sends a few email campaigns that are UCEPRotect flags as SPAM. UCEProtect flags the offending IP, but it also flags the adjacent IPs within the same network. If there are enough SPAM complaints from adjacent IPs, the complaints escalate and can cause an entire network block or even an entire ISPs address block to be blacklisted.

UCEProtects logic (along with some very valid and convincing data) is that ISPs who host one or two SPAMMERS probably host dozens or hundreds of spammers.

SORBS is one of the more difficult blacklists, and it is based on hitting SPAMtraps (aka SPAM Honeypots.) An email servers IP address, sending domain and any URLs that are embedded within an email campaign can get added to the SORBs blacklist and will not be removed for a long time (if ever) unless you specifically request removal. SORBS requires a donation of $50.00 per incident to be removed. (
URIBL uses SPAM honeypots just like does. The difference (we believe) is that URIBL will keep the URL (or domain or sending email address) of the offending domain on their list for an undefined time until any (offending) traffic stops and you clear your domain with URIBL by confirming that the offending problem has been fixed.

Microsoft Frontbridge (88.blacklist.zap not a website)
If you find your emails are getting blocked by recipients who are using Outlook, then you may want to review your MTA logs (email server logs) for references to 88.blacklist.zap. Thats Microsofts internal Frontbridge SPAM filter service that is used to protect anyone using Outlook, and who has their email configured to use Microsofts spam filtering service (which is free). If you have stumbled onto Microsofts blacklist Your email server log will include an entry such as 550 Service Unavailable; host [xx.xx.xx.xx] blocked using 88.blacklist.zap. Please forward this message to Response time is within 24 hours.

Heres how to check if you are being blocked at several major networks:

Roadrunner: (
An excellent blacklist check and removal tool for the Roadrunner (Microsoft broadband) network. The Roadrunner check is very useful because it checks and reports on RoadRunners internal blacklist as well as Cloudmark, ReturnPath, SPAMHaus and more. (
Another excellent and comprehensive blacklist check tool we recently ran across this one checks 120+ blacklists. Note that is not a blacklist it is an aggregate checker i.e., dont send removal requests to them directly.

Surriel: (
Surriel maintains their own private passive blacklist here.

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Article ID: 42
Category: IP, domain or email banning - Spamming
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