.NET 9: Zeroconf discovery is broken

[pcullen1]

Description

Trying to do a Zeroconf host disccovery results in the following error. This used to work on .NET 8:

NetworkInformationException: The requested protocol has not been configured into the system, or no implementation for it exists.

Reproduction Steps

1. Install the latest Zeroconf 3.6.11 into a .NET 9 c# app.
2. Do a discovery, as suggested here: https://github.com/novotnyllc/Zeroconf. Use any protocol

Expected behavior

The list of available hosts will be returned in a list.

Actual behavior

Resolution fails with the following exception: "NetworkInformationException: The requested protocol has not been configured into the system, or no implementation for it exists."

Regression?

This was working in .NET 8.

Known Workarounds

No response

Configuration

.NET runtime 9.0.0
Windows 10.0.19045
x64

Other information

No response

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[CarnaViire]

Related novotnyllc/Zeroconf#266

[pcullen1]

A change was just made in Zeroconf that fixes the problem: novotnyllc/Zeroconf#266 But I'd like to know what changed in .NET 9 that prompted this.

[CarnaViire]

#89990 and #101710 seem to touch the area, but I don't have enough insights. Tagging @wfurt for more info

[wfurt]

Briefly looking at the Zeroconf, I think #89990 is the culprit. We now return more interfaces and some of them may not have IPv4 e.g. trying to fetch that blindly can fail and lead to problems. If anything, it would be interesting to know on what exact interface the app chokes.

[dotnet-policy-service]

This issue has been marked needs-author-action and may be missing some important information.