Spamlists are only used for spam filtering. Technically the server sending out is your server ip. SmarterMail does have a blacklist for inbound connections but this manually modified by system administrators and automated systems like intrusion detection. This is the only system that would prevent an IP from connecting to POP.

Do you see a log entry for their IP in the POP logs?

Hi Matt,

No, we dont have any automated system.

We saw in the logs the report of block by blacklisted, and then we notice that the blocked IP is the client IP.

Only after we white-list the IP the pop connection worked.

Our SM is the 7242

Regards,