The recycled spamtrap
Updated on April 21, 2025
Other common names
Inactive spamtrap, recycled spam trap, reactivated spam trap
The principle
Recycled spamtraps are intended to penalize “unaware spammers,” that is, senders who neglect regular maintenance of their files.
A recycled spamtrap is indeed an email address that has truly existed, which has probably even been collected in the purest respect of the rules, but has been abandoned by its owner for months, even years. And the email service provider has taken control of it, to turn it into a spamtrap.
Most of the time, the ISP puts the address in question through a deactivation phase, during which the sender is notified of the non-existence of the address (bounce). In most cases, a recycled spamtrap is born in this way:
But unfortunately, this is not always the case. Through cross-referencing and in-depth analysis of our server logs, we have already identified recycled spamtraps with a more insidious origin, based on the following life cycle:
These cases are much rarer but formally proven on addresses managed by Microsoft (domains @hotmail., @msn., @live., and @outlook.).
Maintaining your address files therefore implies rigorous cleaning of bounces, but also regular elimination of non-responsive addresses (those that never open your messages).
The duration of the inactivity and/or sleep phases before recycling into a spamtrap varies depending on the operators. However, it seems universally recognized that an address cannot be recycled into a spamtrap less than 12 months after its active phase.
Variant: recycled domains
Some security solution providers, such as Trend Micro, buy domain names that have existed and then been abandoned, in order to give them a second life and use them as trap domains.
How to protect yourself from this?
As mentioned earlier, cleaning bounces is imperative. This operation is automatically performed by OxiMailing, which updates your NPAI list according to the rejection notifications generated by your campaigns. The 360° view available in OxiMailing allows you to easily extract the list of openers from all campaigns, and thereby get rid of non-responsive addresses.
However, all this assumes that your address files are regularly routed in their entirety, at a minimum once a year, in order not to miss the inactivity or sleep phases of an address or domain. It is absolutely necessary to avoid “digging up” a file or a portion of a file that has been set aside for more than 12 months. This is extremely dangerous, not only because of the resulting NPAI rate, but especially because of the high risk of recycled spamtraps that it generates. After 18 months of inactivity, the file must be considered completely obsolete, and the idea of putting it back into service must be definitively abandoned.