DnsGetHostAddresses_LocalhostWithTrailingDot_ReturnsLoopback - SocketException : Name or service not known

[pavelsavara]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1440366
Build error leg or test failing: System.Net.NameResolution.Tests.GetHostAddressesTest

Log

Starting:    System.Net.NameResolution.Functional.Tests (parallel test collections = on [2 threads], stop on fail = off)
    System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback [FAIL]
      System.Net.Sockets.SocketException : Name or service not known
      Stack Trace:
        /_/src/libraries/System.Net.NameResolution/src/System/Net/Dns.cs(526,0): at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, Nullable`1 activityOrDefault)
        /_/src/libraries/System.Net.NameResolution/src/System/Net/Dns.cs(385,0): at System.Net.Dns.GetHostEntryCore(String hostName, AddressFamily addressFamily, Nullable`1 activityOrDefault)
        /_/src/libraries/System.Net.NameResolution/src/System/Net/Dns.cs(87,0): at System.Net.Dns.GetHostEntry(String hostNameOrAddress, AddressFamily family)
        /_/src/libraries/System.Net.NameResolution/src/System/Net/Dns.cs(59,0): at System.Net.Dns.GetHostEntry(String hostNameOrAddress)
        /_/src/libraries/System.Net.NameResolution/tests/FunctionalTests/GetHostEntryTest.cs(413,0): at System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback()
        --- End of stack trace from previous location ---
        --- End of stack trace from previous location ---
    System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostWithTrailingDot_ReturnsLoopback [FAIL]
      System.Net.Sockets.SocketException : Name or service not known
      Stack Trace:
        /_/src/libraries/System.Net.NameResolution/src/System/Net/Dns.cs(526,0): at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, Nullable`1 activityOrDefault)
        /_/src/libraries/System.Net.NameResolution/src/System/Net/Dns.cs(388,0): at System.Net.Dns.GetHostAddressesCore(String hostName, AddressFamily addressFamily, Nullable`1 activityOrDefault)
        /_/src/libraries/System.Net.NameResolution/src/System/Net/Dns.cs(217,0): at System.Net.Dns.GetHostAddresses(String hostNameOrAddress, AddressFamily family)
        /_/src/libraries/System.Net.NameResolution/src/System/Net/Dns.cs(189,0): at System.Net.Dns.GetHostAddresses(String hostNameOrAddress)
        /_/src/libraries/System.Net.NameResolution/tests/FunctionalTests/GetHostAddressesTest.cs(377,0): at System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostWithTrailingDot_ReturnsLoopback()
        --- End of stack trace from previous location ---
        --- End of stack trace from previous location ---
  Finished:    System.Net.NameResolution.Functional.Tests
=== TEST EXECUTION SUMMARY ===
   System.Net.NameResolution.Functional.Tests  Total: 139, Errors: 0, Failed: 2, Skipped: 0, Time: 6.884s

{
  "ErrorMessage": "SocketException : Name or service not known",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1440366
Error message validated: [SocketException : Name or service not known]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 5/29/2026 11:49:34 AM UTC

Report

Build	Repository	Test	Pull Request
1440980	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128702
1440968	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128773
1441013	dotnet/runtime	System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostWithTrailingDot_ReturnsLoopback	#128746
1440985	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128408
1440971	dotnet/runtime	System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostWithTrailingDot_ReturnsLoopback	#128409
1440890	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128705
1440922	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#127690
1440887	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128768
1440811	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128384
1440608	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128553
1440774	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128763
1440691	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128180
1440694	dotnet/runtime	System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostWithTrailingDot_ReturnsLoopback	#127498
1440645	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128752
1440648	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128748
1440597	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#127498
1438994	dotnet/runtime	System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostWithTrailingDot_ReturnsLoopback	#125437
1440575	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128409
1440572	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128750
1440550	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128746
1440438	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128365
1440451	dotnet/runtime	System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostWithTrailingDot_ReturnsLoopback	#128747
1440408	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128448
1440366	dotnet/runtime	System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostWithTrailingDot_ReturnsLoopback	#128745

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
24	24	24

[pavelsavara]

Probably related #127965 and #128068

[dotnet-policy-service]

Tagging subscribers to this area: @karelz, @dotnet/ncl
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[MihuBot]

I'm a bot. Here is a possible related and/or duplicate issue (I may be wrong):

• System.Net.NameResolution.Tests DNS failures: Name or service not known #126641