Why 451 Is Good for You – Greylisting Perspectives from the Early Noughties

Summary

Peter N. M. Hansteen A software vendor was using SMTP spamware to send license keys customers had paid thousands for. A measured rant was in order, and turned out to be quite enlightening. While looking thrugh directories of old material, I stumbled upon what was most likely the main part of a complaint sent to a software vendor for failing to deliver a license key file the company I worked for then had paid some thousands of dollars for. The file as I found it was dated August 2010, but was likely a preserved copy of a draft that was written some time before the first edition of The Book of PF (now in its fourth edition) was published, in response to the non-delivery incident. A quick investigation had me conclude from my spamd logs that their side did not play well with greylisting. Note: This piece is also available without trackers but classic formatting only here. I have revisited the handling sites that do not play well with greylisting theme a number of times, such as the 2018 piece Goodness, Enumerated by Robots. Or, Handling Those Who Do Not Play Well With Greylisting (also here). But I found these early notes interesting enough that I include them here, with only minor redactions to protect the (relatively) innocent: SWCrafters' reaction to finding out that their messages do not get through, essentially blaming "inaccurate spam filtering" was not unexpected, but I will take the opportunity to explain a few things about how Internet email works and how this makes their position at odds with reality. Even though Internet services are offered with no guarantees, usually described as 'best effort' services, a significant amount of effort has been put into making essential services such as SMTP email transmission fault tolerant, making the 'best effort' one with as close as does not matter to having a perfect record for delivering messages. The EXECUTIVE SUMMARY of this message is that the matter which trips up the delivery of SWCrafters' license-carrying email...