Should an ISP use the Policy Block List (PBL) to block its own users?
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Should an ISP use the Policy Block List (PBL) to block its own users?
The Policy Blocklist (PBL) should not be used by an ISP to block its own users.
- Using PBL in this way will create a large number of false positives as it was not designed for this use.
- PBL is only designed to be used on incoming email.
- If the same server is being used for incoming and outgoing email, then the administrator must ensure that authenticated clients are exempted from PBL checks.
- A user may connect from a dynamic IP address that is in PBL and should remain in PBL;
- For users outside of locally whitelisted ranges, use Authenticated SMTP;
- Do NOT use PBL exemptions for this situation: this is not a problem that the use of PBL exemptions was designed to solve.
NOTE: This also applies to using the PBL to deny access to web-forums, journals or blogs.
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