How to open UDP ports?

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1

I can open TCP ports with nftables just fine but for some reason UDP is getting blocked. I can’t even send UDP to localhost. The packet is just never received. Preferably I would like to send packets from one qube to another qube. Is there a trick to get it working? I see someone else had what appears to be a similar issue on github but it was never resolved: firewall udp rule for socks does not allow permitted traffic · Issue #10395 · QubesOS/qubes-issues · GitHub

edit: by the way these are all debian-12 qubes

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2

There is no special trick. It works in exactly the same way as for tcp.
It would be helpful if you were to say what Qubes versions you are
using, and what commands you have tried.

I cannot replicate that GitHub issue under 4.3. (I dont have a 4.2.2
system to test.)

I never presume to speak for the Qubes team.
When I comment in the Forum I speak for myself.

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3

Perhaps run sudo nft list ruleset in the appropriate VM (e.g. sys-firewall) and examine what may be blocking. You can debug further by adding logging rules.

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