WFP duplicate rules

Question

Does the BFE engine or ( overall firewall engine) handles duplicate rules by throwing replications, if accidentally add a specific rule multiple times ?

Thanks,
Prokash

Answer 1

Hi,

Welcome to Microsoft Q&A!

For more details about the logic built into the Windows Filtering Platform (WFP), I suggest you could refer to the Doc: Filter Arbitration

Does the BFE engine or ( overall firewall engine) handles duplicate rules by throwing replications, if accidentally add a specific rule multiple times ?

Every filter in the Windows Filtering Platform (WFP) has an associated weight, which is used during filter arbitration. For example: The filter weight used by the Base Filtering Engine (BFE) is of type FWP_UINT64.

When two or more callouts are registered at the same sublayer, problems may occur when the same weight is assigned to the filters. This issue can be prevented by having callouts create their own sublayer by using FwpmSubLayerAdd0.

For more details, I suggest you could refer to the Doc: Filter Weight Assignment

Regarding duplication , As far as I'm concerned that's ok as long as the filter weights in the sublayer are not duplicated.

Best Regards,

Jeanine

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