Blacklists are found in thousands on the internet. Some of these blacklists are available for free while many providers buy authenticate blacklists from various legitimate internet monitoring groups. Basically, these blacklists contain ip addresses and information about emails used by spammers. IP addresses of mail services sending out spam emails will also be included in the blacklists. Simply, all kinds of blacklist sites will be available in blacklists.
ISPs and bandwidth providers will check blacklists before delivering any email. IP address of the sender is checked against blacklist used by the provider. It is not possible to find out what list is used by the ISP and bandwidth provider. Aside from public blacklists, companies will have private blacklists for more detailed checking.
Blacklist test is employed by email monitoring tools. These tools will use available known blacklists to perform the test. When your IP address is blacklisted in any of those known lists, you will be notified. Groups that are interested in keeping the internet clean will be engaged in creating these blacklists and hence, if you contact them, you can get your ip address whitelisted.
Many entrepreneurs lose their subscribers mainly because they don’t check blacklists. While it is practically impossible to manually check your IP address against blacklisted list of IP addresses, a tracking tool can be of great help. If you think that you have to spend a great deal of money to buy a monitoring tool, then you are wrong. You can easily find a good email monitoring and tracking software that can help you in doing all kinds of blacklist tests.
The tool you use for checking blacklists must constantly update itself because everyday, many new domains and dns are added to the blacklists by internet users. Also, the tool must be able to use as many blacklists available to increase email deliverability.
There are several hundred SPAM blacklists that can impact your email marketing results but luckily, there are a few tools that can help you check most of them quickly. We’ve included here a handy reference with the sites that you can use to check your blacklist status. We’ve also highlighted a handful of the more prominent SPAM blacklists.
What you need to know to check Blacklist status
Most SPAM blacklists track the reputation of the email servers that are being used to send outgoing email marketing for your domain> To get started – you’ll need to know the IP address of the email servers sending emails for your company. If your company uses its own servers to send email campaigns, you’ll need top know the IP addresses of those servers. If your company is sending email campaigns via an Email Service provider (“ESP”) then you’ll need to know the IP addresses of their servers or specifically – what IP addresses are being used for your domain (if you have a dedicated IP address as part of your service). You can usually get this information by asking your IT support staff, or alternatively send an email to yourself and select the ‘view headers’ option in your email client. The header option will indicate the IP address your email was sent from.
Some SPAM blacklists track more than IP’s – they also track domains, URL’s 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’ll list the specific email content as SPAM.
Here are 3 sites where you can check multiple public blacklists if you know your servers IP address(es):
mxtoolbox. MXToolbox is free and allows you to check about 100 blacklists at the same time. Just go to the site, then select ‘blacklist’ to run the blacklist test. Enter the email service IP addresses and mxtoolbox checks all 100 in 30 seconds or less.
DNSStuff. This blacklist check is also free, but DNSStuff includes a whole toolbox of other IP and networking tools. DNSStuff’s additional services are inexpensive (almost free) service where you can check 97 blacklists.
DNSBL.info. (Domain Name System Blacklist). This is a free blacklist checking service. Checks about 80 blacklists
A Few blacklists deserve special mention
One of the most widely used blacklists, SPAMHaus.org’s mission is to rid the world of unsolicited commercial email (“UCE”) by creating and monitoring a network of millions of ‘spam honeypot’ email addresses. These are email addresses that are expired, or that never were ‘real’ recipients that Spamhaus acquires from ISP’s. 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 it’s a pretty good system but not flawless in our experience. For example, if you are capturing registration information from your website or from online events, an ill-willed deviant can enter a bogus / honeypot address into your list. Your well-intentioned campaign gets caught and viola – you are on Spamahaus’ 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).
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. UCEProtect’s ‘guilt by association’ approach means your servers can be blacklisted if your ISP hosts other systems that are caught for SPAMMing.
Here’s an example. Your company’s servers are hosted with ‘hosting-company.com’ (we made that up just on case you weren’t sure). Now, assume ‘hosting-company.com’ hosts hundreds of thousands of companies and has 30,000 IP’s under management, including your one, lonely email server. One day, a SPAMMER who is a customer of ‘hosting-company.com’ 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 ISP’s address block to be blacklisted.
UCEProtect’s 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 server’s 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 Spamhaus.org 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. That’s Microsoft’s internal Frontbridge SPAM filter service that is used to protect anyone using Outlook, and who has their email configured to use Microsoft’s spam filtering service (which is free). If you have stumbled onto Microsoft’s 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 delist [at] frontbridge.com. Response time is within 24 hours.