Are you currently vulnerable to blocklisting?

Achieving high levels of deliverability has never been of such paramount importance as it is today. Because of the surge in email sending, professional services marketers will need to be wary of the risk of blocklisting and the detrimental implications it could have on their firms.

Here we explain what blocklisting is and how it can happen.


What is blocklisting?

We live in the age of consent and permission-led marketing, where firms need to adhere to regulatory compliance and ‘good manners’ when it comes to emailing a contact.  Without it, the professional services sector cannot build trusted brands and strong relationships.  But that’s not always the case. There are still untrustworthy individuals or spammers who aim to distribute unwanted content that may be harmful – and that does not comply with anti-spam laws. 

Blocklists exist to help identify IP addresses or domains that are known to send spam or distribute harmful content. These lists are utilised by internet service providers (ISPs) to help protect firms from spam hitting their systems. Professional Services firms will need to be vigilant in their eMarketing processes to avoid the risk of being blocklisted, and we know how important it is for you to have reliable email deliverability.

How does blocklisting happen?

Every time an email is marked as spam, either by a contact or by a spam filter, it triggers an action against the sender’s IP or the domain.  When there are a certain number of actions marked against an IP address, this IP is automatically added to the blocklist.

Spam traps are email addresses that are never used for genuine mail. In most cases, you wouldn’t be able to identify that an email is a spam trap address. The only indication to determine a spam trap is behaviour.

There are three main types of spam traps:

Recycled: These addresses originally belonged to a contact before becoming inactive. The email address bounced due to being invalid, then converted to a spam trap.

Pristine: These addresses have been set up purely to operate as a spam trap, they have never been created by contact.

Typo: These addresses are domains misspelt, for example, or Spam trap networks purchase these typo domains and allow them to accept mail. 

In Professional Services, the most at-risk method is recycled and low engagement rather than pristine and typo, this is due to the nature of our space, not lending to list acquisition. So whilst purchased lists are the most common threat it does not mean Professional Services firm's are safe.

But it is not just being marked as spam that can result in an IP address being blocklisted. There are other factors which digital marketers need to be aware of.  One of these is email engagement.  If a contact chooses to delete an email before opening it, or there are no replies or click-through rates, it could be that the recipient does not want to receive the email.  Consistent signs of low engagement levels are enough to flag that you may be breaking anti-spam law and – yes, you will end up on a blocklist!

Operating regular marketing list health checks/audits is more critical now so more than ever due to the swell in email volume during the pandemic. Are you sending to contacts that haven't engaged with you in the last 12 months? Reduce your email wastage and maximise your deliverability through routinely cleaning your database.

Who is responsible for BLoCKLISTING?

Internet service providers (ISPs) and international blocklisting organisations such as Spamhaus, Barracuda, or Spamcop are always on the lookout to help identify the IPs and domains used to send out unsolicited mass email or spam and add them to a ‘blocklist'. If the sending IP appears on a blocklist, emails sent from that IP address will be blocked from being delivered to the recipients.

Anyone can get blocklisted, this is true, but typically it only takes up to 24 hours to be removed from a listing. In these cases, the incident may seem like a blip, but there are cases in which blocklisting can pose a severe threat to your client communications. Despite the efforts that the Legal & Professional Services market demonstrates to be compliant, our world was rocked only recently with phishing scams hitting one ESP & an unprecedented blocklisting incident hitting another. It was considered unprecedented because the listing left leading firms unable to send business-critical communications for several days. The question is: what might cause such a catastrophe? Likely a severe spam issue across multiple connected IP addresses.

Interesting to note, It is extremely unlikely for an ESP to be blocklisted across all IPs and to be down for a number of days.  Only these blocklisting organisations decide what IPs or domains are listed or removed. The only way to be removed from a listing is for an ESP to fix the problem that caused the issue.

How does an ESP infrastructure support against blocklisting?

It is essential to note the value of what happens behind the scenes at an ESP that ensures clients are safer from blocklisting. There are many points to consider, but your focus areas should be the following five points and how they impact risk.

Sector expertise 

You should always look at the bigger picture in regards to your provider. Finding an ESP that presents a niche market offering whether that be through infrastructure setup and/or sector-specific solutions has a significant impact as to the level of risk you are exposed to. For example, ESPs working solely within the legal, financial and professional services sectors run a lower risk profile due to the nature of communication - mass mailing is frowned upon in favour of targeted sending to high-value clients and contacts. Should you be using a provider that accommodates sectors running poor practises around list acquisition & mailing methods, you are automatically at higher risk.

Sender IP reputation score

Sender reputation score is a complex matter that is impacted by a number of factors, including your sending volumes and bounces. The lower your score, the more likely you are to flag the attention of an ISP in a negative manner. On the flip side, consistent volumes and favourable deliverability will maintain a high sender score generally. ESP's often house multiple clients on one IP, by grouping sets of clients with lower sending volumes they are able to improve the overall sender score as a collective. They do this because leaving the clients to run lower volumes alone is bad news! Coupled with poor data hygiene, this is one of the riskiest places to be and has a direct impact on IP reputation.

Wide range of sender IP availability

ESP's across the globe have different infrastructure models based on size, sector expertise and clientele. Ensuring that the infrastructure offers a wide set of sender IP availability increases the level of efficiency and flexibility with which they can respond to the situation in the event of blocklisting. In the interest of clients, ESP's can minimise platform downtime through efficient incident response process, communication and technology. Nonetheless, this is often an overhead that some ESP's do not cover due to the rare nature of the situation. A risk that can come back to bite them if they're not ready!

Mail throttling

It's commonplace in professional services that firms will set strict administrative rules around email filtering and quarantine to reduce the risk of spam and attack. The challenge is that some of these firms may be your key clients, so it's of paramount importance that your emails get through to them. Enabling mail throttling allows for an ESP to identify how often you are sending to a particular client's domain at any given time. This is beneficial because ensuring that you're not sending high volumes to the same server repeatedly mitigates the risk of being flagged as spam by the ISP's at those firms.

Security grades

Security is a critical yet widely hidden factor when considering the risk profile of your ESP. It is important to ensure that your platform is equal to, if not better than, the calibre of security expected by your partners, colleagues and clients. Your ESP should set security high in their priorities when it comes to data and infrastructure. They should seek to improve how the system operates and reduce general risk through varying measures from encryption to spam analysis and security protocols.​

HOW emails bounces can impact blocklisting

Bounces are classified in two ways; hard and soft. A soft bounce typically means that the email address is legitimate but won’t accept an email at this time. This could be because the mailbox is full, or the system is unable to make a connection with the receiving mail server. A hard bounce means that the email address does not exist and cannot be sent to. This can either be because the email address has been incorrectly inputted, and doesn’t represent a real email address, or the address has been deactivated, for example, when a contact leaves a company. Bounces mean that the email address has not been received, and why a contact hasn’t seen an email.

So, if you have an old list with clients or partners who are no longer at a firm, for example, these are likely to be hard bounces.  If you have a consistent amount of high bounce rates, you could be blocklisted. This is because email service and internet providers monitor bounce rates as an indication of spamming activity. It’s a compelling reason to keep your firm's marketing lists up to date!

If you’re concerned about the threat of being blocklisted, or simply want to find out more information. Please do not hesitate to get in touch with any questions or concerns you may have.