Wireshark mailing list archives
Re: Are Capture Filters Implemented in Software or the Network Card?
From: Gene Cumm <gene.cumm () gmail com>
Date: Sun, 21 Nov 2021 11:50:38 -0500
On Sun, Nov 21, 2021, 11:27 AM X Q <xq1xq1xq1 () gmail com> wrote:
This is a question fairly deep in the guts of Wireshark that I could not find an answer to. When a capture filter is implemented are ALL packets sent to Wireshark/Dumpcap/TShark at the software level for filtering or are the packets not matching the filter shedded/ignored by the Network Interface card itself thus reducing strain on the CPU/Network Fabric? I look forward to hearing from you! ___________________________________________________________________________ Sent via: Wireshark-dev mailing list <wireshark-dev () wireshark org> Archives: https://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://www.wireshark.org/mailman/options/wireshark-dev mailto:wireshark-dev-request () wireshark org ?subject=unsubscribe
Iirc, implemented in the capture library. If you're using npcap on a traditional card, pure software. That said, I can recall doing a 1Gbps capture of mostly full size frames on an Intel card with 0 issues. Promiscuous mode drops the hardware filter (presumably still present) for destination broadcast or self to all frames. What's the goal? How much traffic are you really capturing? Is there really a CPU constraint? --Gene
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Current thread:
- Are Capture Filters Implemented in Software or the Network Card? X Q (Nov 21)
- Re: Are Capture Filters Implemented in Software or the Network Card? Gene Cumm (Nov 21)
- Re: Are Capture Filters Implemented in Software or the Network Card? Nicolás Alvarez (Nov 21)
- Re: Are Capture Filters Implemented in Software or the Network Card? Guy Harris (Nov 21)
- Re: Are Capture Filters Implemented in Software or the Network Card? Graham Bloice (Nov 21)
- Re: Are Capture Filters Implemented in Software or the Network Card? Guy Harris (Nov 21)
- Re: Are Capture Filters Implemented in Software or the Network Card? Gene Cumm (Nov 21)
- Re: Are Capture Filters Implemented in Software or the Network Card? Guy Harris (Nov 21)