Is SSDP traffic filtered inside Actions runners? (unit test is breaking as no notification is received, but locally passes)

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Hey,

My unit tests are failing as they hang when binding to the SSDP UDP port (1900) and in the same test, another client socket is created, that sends UDP multicast to well known SSDP multicast address and port. (it's a private repo, so I can't send the actual run link)
The test runs inside a devcontainer (through the devcontainers/ci@v0.3 action), and locally using the same devcontainer image the tests are passing with no issue.
Is there any firewall rule that blocks this traffic? I only found info about ICMP is blocked on the Actions Runner servers, but SSDP is not mentioned at all.

Thanks & BR