The Spamhaus Project


How to avoid looking like a spammer when sending marketing emails

Here are a few key elements to abide by to ensure an ISP or blocklist provider doesn't view your marketing emails as malicious.

by The Spamhaus TeamFebruary 15, 20222 minutes reading time

The day-to-day running of an email program opens up as many pitfalls of appearing like a spammer as the program’s set-up does. Here are a few key elements to abide by to ensure an ISP or blocklist provider doesn’t view your marketing emails as malicious:

  1. Spammers often send email erratically; therefore, a steady sending pattern is essential. Bursty mailings or sudden and significant changes in volume are things that infected hosts do. Remember that an ISP’s filtering systems do not know or care that your company is trying to make money on Mother’s Day retail activity – if your sending patterns mimic an infected host, your email will not get through!
  2. Never send to a suppression list by accident. The phrase “we sent the wrong segment by accident” has been used by spammers to the point that it has created a knee-jerk response in ISP abuse-desk workers. Do NOT let this mistake happen: render such an event completely impossible!
  3. Given the various questionable ways that miscreants acquire mailing lists for their malicious campaigns, their unknown user rate per send is likely to be high. Hence it’s vital to ensure a low rate of unknown users in any given send.
  4. A spammer’s care factor is almost 0% regarding reputation – they burn through IP addresses and domains. Yours does matter, so keep an eye on all of your sending metrics, including unexpected bounces, temporary failures, and anything that could indicate abnormalities in the mail stream. If you’re an Email Service Provider (ESP), keep an eye on your SMTP logs.
  5. A cybercriminal’s engagement rate doesn’t need to be high – sometimes, they’re just looking for a few victims per email campaign. This is why your engagement rate does need to be high. Where possible, use a “preference center” to let people choose what content they’re interested in receiving from you to maximize engagement rates.
  6. Don’t send attachments with emails – one fundamental way a cybercriminal delivers their malware payload is via an attachment.

With these elements covered, we will be delving into the fundamentals of address acquisition to ensure you’re building your mailing lists appropriately without potentially damaging your email reputation.