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We’re always happy to investigate new blacklists to see how they work for our customers and how they provide additional information on our customers’ email deliverability. If anyone ever has a blacklist that they suggest we add, please email us.
Over the last few weeks, we’ve given SPFBL, a Brazilian-based DNS Blacklist, a trial here at MxToolbox. Like all new Blacklists, our trip included display of results with low severity. However, during the trial we noted that the majority of customers reporting issues with this blacklist were due to simple, and routine reverse DNS issues. For example, reverse DNS might point to a 3rd party load balancer application, which in no way should break email delivery.
Since this is the case, we’ve decided to suspend use of SPFBL until utility of the list changes.
Recently, we’ve received a number of enquiries about delisting with Protected Sky. For the last week or so, Protected Sky has had a maintenance notice reminding users that delisting is not available. Over the weekend, they added another announcement:
Automatic removal will occur for IPs that are seen to be clean
MxToolbox Support is currently trying to contact Protected Sky for clarification, but we have an operating theory. Currently, we believe this to mean that they have a system in place to automatically delist an IP address if it is not captured in one of their spam traps or reported by one of their customers as spam.
Once we have confirmation or update from Protected Sky, we will update this post with more information.
Blacklists came about as a response to unethical and illegal spam. Blacklists have no other purpose but to stop bad or malicious acts, so they typically occupy the ethical high ground. Since they are used by businesses, universities and internet service providers to screen traffic, they are incented to be ethical, list only known bad actors and not list legitimate commercial traffic. To do otherwise would undermine the value of their service to their own customers.
All that said, MxToolbox carefully curates a list of the most used and best maintained blacklists. All the blacklists we check provide free delisting services. We feel that requiring payment for delisting is not ethical. However, a few blacklists offer expedited delisting services, which is a bit of a grey area. Other blacklists may ask strange or seemingly random questions. Think of this as geeks being geeks, rather than anything malicious or unethical.
Being on a blacklist is a sign of trouble for your email deliverability. Since companies screen out traffic from blacklisted IP addresses, your emails may be dumped into a spam folder or refused completely. If your email server’s IP address is blacklisted, it could make doing business difficult. It’s also a sign that your servers may have been used for spreading spam, viruses or malware. This could indicate a security breach or an employee issue.
If your website IP address is blacklisted, then you have a bigger problem. Typically, web servers do not send email. Since the primary means of collecting bad actor IP addresses is via email, your web servers might be sending email without your knowledge. This is definitely a sign of a malware or virus infection on those servers, or someone running email inappropriately from a web server.
Occasionally, small businesses will run email and web on the same servers. If you do, you run the risk of a blacklist event taking out all your e-commerce channels because companies may deny access to your website and email activity based upon your blacklist status.
Domain blacklisting is a serious issue. It means that someone is using your domain for malicious activity, either on a server hosting your website, or by breaking into your DNS. If the activity is coming from a server in your datacenter, then you need to root out the virus or malware on your servers, patch your servers, and upgrade your security systems and firewalls. If the activity is coming from a server outside your datacenter that is using your domain name or a subdomain, you have another big problem. In this case, your DNS has been hacked and the attackers have added subdomains that use your brand. The attackers can utilize the remote server to host malware and viruses all the while using your brand to make their attacks look legitimate.
Regardless of the type of blacklist, being blacklisted could be a serious issue. MxToolbox Monitoring services can help you by letting you know when you have been blacklisted, giving you notice before it becomes a serious business issue.
While we were improving our unsubscribe code, we reset our email filters. This had the effect of triggering a new email to all our existing customers. You can disregard the email. Nothing has changed with your account status.
Each blacklist has it’s own method for delisting. Sometimes it’s a webform, sometimes it is an email. Almost always, you need to include the steps you took to fix whatever problem put you on a blacklist. Many blacklist operators see themselves as righteous crusaders fighting against spam, malware, viruses, bad email configurations and poor email operations, so remember when dealing with a blacklist operator, you are the bad actor seeking forgiveness.
After you’ve gone through these steps, you should consider setting up monitoring on your important IP addresses, especially Email and Web servers. Monitors can alert you to blacklist events as they emerge, rather than waiting for serious business impacts. MxToolbox offers a wide range of monitoring solutions from Free, single IP solutions, to real-time large network blacklist monitoring.
Typically, the first time you find out that you are blacklisted is when customers start telling you that they aren’t receiving your email. Bounced email is the number one symptom of being blacklisted. Unfortunately, this is finding out about the problem only after it has impacted your business.
The other way to find out if you have been blacklisted is monitoring. MxToolbox provides active monitoring solutions for blacklisting events. Our free IP Blacklist monitor checks your server’s IP address every 7 days to give you a general warning of blacklist issues. Our paid subscriptions check every 4 hours and premium services check at least once an hour, up to real-time blacklist checking. The higher the frequency of checks, the more likely you will know about being blacklisted before it becomes a customer issue.
Organizations use blacklists to limit security threats like spam, malware and viruses. The IP address of a server sending email is pulled from the email’s header and compared to the blacklist. Anything that originates from an IP address on the blacklist is refused, quarantined or dumped to a spam folder. Similarly, content of an email is scanned against the domain blacklist. Any emails from or containing a domain on a blacklist will be dealt with.
Some companies also utilize blacklists to scan inbound or outbound web traffic or to create web or email filtering appliances. Many companies purchase or utilize multiple blacklists along with their own blacklist information to minimize the potential for spam, malware or viruses passing through their servers.
MxToolbox provides insight into the blacklist reputation of your IPs and Domains.