Eighteen Years of Greytrapping – Is the Weirdness Finally Paying Off?

3 days ago

Greytrapping spamtraps at nxdomain.no (bsdly.net) started as an experiment in 2007, evolving from a Debian to OpenBSD/FreeBSD setup with spamd for greylisting and spamtrapping.
The number of spamtraps exceeded Norway's population on August 7, 2025, reaching 5,620,384 and growing over time, with data on additions and trapped hosts tracked since 2017.
Greytrapping effectively reduces spam by using network-level tricks and SMTP protocol interpretations, making mail service management simpler and reducing server load.
Over the years, spamtrap sources expanded from greylist extraction to include SSH, POP3 logs, and synthetic generation from spamd logs, with a surge in synthetic entries from late 2024.
Data shows yearly and monthly trends in spamtrap additions, with notable peaks in 2019 and 2025, and a general decline in trapped hosts despite consistent delivery attempts.
IPv6 support is a limitation as spamd is IPv4-only, hindering effectiveness against IPv6 traffic, though many spammers still use IPv4.
The article targets those running or considering their own mail service, recommending Michael W. Lucas' book 'Run Your Own Mail Server' for guidance.
Historical articles and field notes document various incidents, including interactions with major email providers and odd spam campaigns, highlighting ongoing challenges in email management.

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