Imagine the scenario; you’ve worked hard all week hitting deadlines and producing eye catching email creative that renders beautifully on multiple devices, now all you want to do is wind down by hitting a nightclub. So you dash home, pull your favourite shirt from your wardrobe and head into town.
After seemingly waiting for hours, and cursing those who jump the queue, you get to the door only to get turned away. Naturally you try to find out why you’ve been denied access to that ice cold mojito and those funky beats. The bouncer says “you’re on our barred list” and shows you a picture that could, through squinted eyes, look vaguely like you, had you been raised by a pack of wolves. Despite protesting, you get turned away so reluctantly head home feeling dejected, after all, you’d done nothing wrong!
Back at work on Monday, you’re looking last week’s campaign results and notice that you have an abnormal amount of hard bounces, upon closer inspection you see the words “550 5.7.1 Connections not accepted from IP addresses on Spamhaus”. You’ve just been turned away from the club, it’s like Friday night all over again!
Spamhaus is one example of many Blacklists that ISP’s may choose to employ in a similar way to the nightclub bouncer and his “barred list”. Blacklists can take several forms but their general purpose is to help ISP’s block known spammers either by indicating that they should refuse entry or apply additional filtering to the email.
Just as a nightclub would have terrible problems if it let everyone in without checking their credentials, ISP’s would be flooded with spam and their networks would quickly grind to a halt. According to Commtouch, around 75 percent of all email sent in the first three months of 2012 was spam so ISP’s need to protect their customers by filtering it out and ensuring that legitimate email can be delivered. By using blacklists, an ISP can reduce the amount of spam entering its network by as much as 80%.
All ISP’s use different blacklists and they may be compiled from the many public blacklists or the ISP’s own internal blacklist. Public blacklists have varying approaches to listing and various definitions of spam, of which I think the term “troublesome email” may sometimes be a better description. If you send email that system administrators find “troublesome”, generates a high amount of complaints or poor feedback then you could easily find yourself blacklisted. An ISP’s internal blacklist is typically built to reflect spam complaints, unknown user rates and server configuration problems.
IP blacklists such as those provided by SORBS, Spamhaus and SpamCop are employed by ISP’s for use on their inbound servers to check the IP address of the sending server requesting a connection and identify problem senders such as those with open-relays, open-proxies, known spammers or ISP’s that allow spammers to use their infrastructure.
Domain, or more correctly URI blacklists operate in a similar way but, they are used to check the domain names and IP addresses (URI’s) inside the email to determine if they have been seen in previously reported spam messages. This allows for the blocking or filtering of spam messages from different IP addresses, from addresses and with varying creative copy. Well known URI blacklists such as SURBL, URIBL.com and DBL from Spamhaus are commonly used by ISP’s to help determine if your email should arrive in subscribers inboxes.
So, how do you find out if you’re on a blacklist? You may have already noticed by looking at your bounce logs and seeing responses such as “Mail Refused - IP Address xxx.xxx.xxx.xxx Blacklisted” or “550 Service Unavailable; host xxx.xxx.xxx.xxx blocked” but if you haven’t seen these messages then you should start actively monitoring for blacklisting so you can react quickly to resolve issues as they arise. Return Path’s Blacklist Alert will monitor all your outbound mail activity and notify you immediately should you be listed on any of the important blacklists. Furthermore, you’ll also get information on the reason for blacklisting and how to get the listing removed before your campaign performance is significantly affected.
In my experience, some blacklist operators, like nightclub doormen can be difficult to negotiate with without an intermediary such as Return Path and will demand the introduction of unfeasibly high standards before considering de-listing. This could have a devastating effect on your business, not being able to deliver email for your clients may mean you find yourself in serious financial difficulty in a short space of time. So the best way to avoid problems is to not send anything that could get you in trouble in the first place and to monitor and maintain a good reputation so you’re not turned away from the club.
Finally, it is important to remember those people jumping the queue at the nightclub because they were the type of smartly dressed high class clientele that the club needs to maintain its reputation with customers. By operating a good email program you will be eligible to join this list of VIP’s that ISP’s will want to let in, we call our VIP list the Return Path Certification program and it’s the most respected whitelist in the email universe. Read more about it here: http://www.returnpath.net/commercialsender/certification/