TryGetNameInfo_LocalHost tests failing with HostNotFound

[danmoseley]

In NameResolutionPalTests, using last night's sources, these are all failing for me on Windows 10 21H1

TryGetNameInfo_LocalHost_IPv6_TryGetAddrInfo(true|false)
TryGetAddrInfo_LocalHost_TryGetNameInfo
TryGetNameInfo_LocalHost_IPv6
with
Assert.Equal() Failure\r\nExpected: Success\r\nActual: HostNotFound

I can ping localhost from the shell. Not sure how to troubleshoot further.

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Issue Details

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In NameResolutionPalTests, using last night's sources, these are all failing for me on Windows 10 21H1

TryGetNameInfo_LocalHost_IPv6_TryGetAddrInfo(true|false)
TryGetAddrInfo_LocalHost_TryGetNameInfo
TryGetNameInfo_LocalHost_IPv6
with
Assert.Equal() Failure\r\nExpected: Success\r\nActual: HostNotFound

I can ping localhost from the shell. Not sure how to troubleshoot further.

Author:	danmoseley
Assignees:	-
Labels:	area-System.Net, untriaged
Milestone:	-

[danmoseley]

The next step if I looked further might be to create a repro in C. I won't have time to look myself at least for a while, and it's not a problem to ignore these 4 tests for now if it's just me.

[karelz]

@danmoseley is it 100% repro on your machine? I don't think we saw it anywhere else ...

[danmoseley]

I'll close until I have time to dig in further.

[danmoseley]

It seems to repro on my machine. Is there anything I can gather to help

[danmoseley]

TryGetNameInfo_LocalHost_IPv6 and TryGetNameInfo_LocalHost_IPv6_TryGetAddrInfo fail here

string name = NameResolutionPal.TryGetNameInfo(new IPAddress(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }), out error, out nativeErrorCode);

it appears that on this machine, it cannot resolve this to localhost.

I noticed this line in another file which sounds like this:

runtime/src/libraries/System.Net.NameResolution/tests/FunctionalTests/TestSettings.cs

Line 22 in f5ec451

// Windows CI servers not configured with IPv6 name resolution.

I haven't done anything special to my machine. presumably it's configured a little differently. @wfurt is there a way to tell that this won't work, so it can skip?

[wfurt]

What ipconfig /all gives you @danmoseley ?

[danmoseley]

Sent offline. Also,

C:\>ping 0:0:0:0:0:0:0:1

Pinging ::1 with 32 bytes of data:
Reply from ::1: time<1ms