Feature #13868


Allow packet capture on unassigned interfaces

Added by Andrew B 3 months ago. Updated 2 months ago.

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I want to be able to capture packets on the base physical interface for a physical interface that only has assigned VLAN interfaces, no assignment on the physical interface itself.
For example, the setup I have is somewhat like this

igc2: <unassigned>
igc2.10: guest
igc2.20: staff
igc2.30: contractors
igc2.40: admins
igc2.4090: mgmt

There are 2 reasons I want to do this:
  1. So I can do a promiscuous mode capture on the whole interface and pick up packets for all VLANs (even ones that I haven't defined) with their 802.1Q header
  2. So I can check to see if the device on that interface is sending untagged packets or packets to VLANs I don't expect while trying to debug an issue I'm facing

The base interface still exists and is up, so I can run tcpdump -i igc2 from a terminal and that will capture what I want but it's a pain to save it to a dump file and download it to a computer with Wireshark.
It's not possible to do this from the Web UI since igc2 has no assignment. If I do assign the interface it seems to mess up the VLAN interfaces receiving packets correctly so having a temporary or bogus assignment is not a good option.

I can imagine several other situations where a specific interface (physical or virtual/logical) has no assignment but is active and a packet capture may be desired.

Related issues

Related to Feature #13382: More flexible packet capture GUIPull Request ReviewMarcos M

Actions #1

Updated by Marcos M 3 months ago

Actions #2

Updated by Marcos M 3 months ago

  • Status changed from New to Pull Request Review
Actions #3

Updated by Marcos M 3 months ago

  • Assignee set to Marcos M
  • Target version set to 2.7.0
  • Plus Target Version set to 23.05
Actions #4

Updated by Danilo Zrenjanin 2 months ago

I tested the commit da2879b467746b43c8b8687700b6d7f34d4fd302 against the 22.05 release.

I was able to capture on unassigned interfaces. All worked fine.


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