DNS localhost subdomain tests with AddressFamily fail on Android #124751

Closed
#127742
#125478
Closed
DNS localhost subdomain tests with AddressFamily fail on Android#124751
#127742
#125478
Assignees
simonrozsival
Labels
Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
Milestone
11.0.0

Description

@rzikm
rzikm
opened on Feb 23, 2026

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
Build error leg or test failing: System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily, System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily

Error Message

Fill the error message using step by step known issues guidance.

{
"ErrorMessage": "LocalhostSubdomain_RespectsAddressFamily",
"ErrorPattern": "",
"BuildRetry": false,
"ExcludeConsoleLog": false
}

Description

The DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily and DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily tests (introduced in PR #123076 for RFC 6761 localhost subdomain handling) consistently fail on Android CI (windows.11.amd64.android.open queue).

Error

System.Net.Sockets.SocketException : hostname nor servname provided, or not known
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryCore(String hostName, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntry(String hostNameOrAddress, AddressFamily family)

Analysis

  • The tests call e.g. Dns.GetHostEntry("test.localhost", AddressFamily.InterNetwork) (or InterNetworkV6).
  • The RFC 6761 implementation tries the OS resolver for "test.localhost" first, then falls back to resolving plain "localhost" with the same AddressFamily.
  • The double GetHostEntryOrAddressesCore in the stack trace confirms the fallback triggers but also fails.
  • The fallback calls getaddrinfo("localhost", ..., ai_family) with a specific address family (AF_INET or AF_INET6). On Android, this may fail (EAI_NONAME) while getaddrinfo("localhost", ..., AF_UNSPEC) succeeds.
  • Other localhost subdomain tests that use AddressFamily.Unspecified (e.g. ReturnsLoopback) pass on Android.
  • There are no non-[OuterLoop] tests that call Dns.GetHostEntry("localhost", AddressFamily.InterNetwork) directly to confirm if family-specific localhost resolution works on Android in general.

CI Data (last 14 days, main branch)

BuildGetHostEntry failuresGetHostAddresses failures
130373533
130431211
130494322

Each Android job has exactly 1 failure per test (the test has 2 InlineData values: InterNetwork and InterNetworkV6), suggesting only one address family variant fails per run.

Console log example

https://helixr1107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-heads-main-76f79e897d5246b58a/System.Net.NameResolution.Functional.Tests/1/console.858b3560.log?helixlogtype=result

Possible fixes

  1. Fix the fallback to resolve "localhost" with AddressFamily.Unspecified and then filter results by the requested family.
  2. Investigate whether family-specific getaddrinfo("localhost", AF_INET/AF_INET6) is expected to work on Android and fix the emulator setup.

Known issue validation

Build: 🔎https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
Error message validated:[LocalhostSubdomain_RespectsAddressFamily]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 2/23/2026 12:30:22 PM UTC

Report

BuildDefinitionTestPull Request
1408366dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
1404759dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
1388248dotnet/runtimeSystem.Net.NameResolution.Tests.GetHostEntryTest.Dns_GetHostEntryAsync_IPAddress_Ok#127192

Summary

24-Hour Hit Count7-Day Hit Count1-Month Count
123

Metadata

Metadata

Assignees

Labels

Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android

Type

No type

Projects

No projects

    Milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions

    , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
     blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

    Skip to content
    DNS localhost subdomain tests with AddressFamily fail on Android #124751
    Closed
    #127742
    #125478
    Closed
    DNS localhost subdomain tests with AddressFamily fail on Android#124751
    #127742
    #125478
    Assignees
    simonrozsival
    Labels
    Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
    Milestone
    11.0.0
    Description
    @rzikm
    rzikm
    opened on Feb 23, 2026
    Build Information
    Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
    
Build error leg or test failing: System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily, System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily
    Error Message
    Fill the error message using step by step known issues guidance.
    {
"ErrorMessage": "LocalhostSubdomain_RespectsAddressFamily",
"ErrorPattern": "",
"BuildRetry": false,
"ExcludeConsoleLog": false
}
    Description
    The DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily and DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily tests (introduced in PR #123076 for RFC 6761 localhost subdomain handling) consistently fail on Android CI (windows.11.amd64.android.open queue).
    Error
    System.Net.Sockets.SocketException : hostname nor servname provided, or not known
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryCore(String hostName, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntry(String hostNameOrAddress, AddressFamily family)

    Analysis
    • The tests call e.g. Dns.GetHostEntry("test.localhost", AddressFamily.InterNetwork) (or InterNetworkV6).
    • The RFC 6761 implementation tries the OS resolver for "test.localhost" first, then falls back to resolving plain "localhost" with the same AddressFamily.
    • The double GetHostEntryOrAddressesCore in the stack trace confirms the fallback triggers but also fails.
    • The fallback calls getaddrinfo("localhost", ..., ai_family) with a specific address family (AF_INET or AF_INET6). On Android, this may fail (EAI_NONAME) while getaddrinfo("localhost", ..., AF_UNSPEC) succeeds.
    • Other localhost subdomain tests that use AddressFamily.Unspecified (e.g. ReturnsLoopback) pass on Android.
    • There are no non-[OuterLoop] tests that call Dns.GetHostEntry("localhost", AddressFamily.InterNetwork) directly to confirm if family-specific localhost resolution works on Android in general.
    CI Data (last 14 days, main branch)
    BuildGetHostEntry failuresGetHostAddresses failures
    130373533
    130431211
    130494322
    Each Android job has exactly 1 failure per test (the test has 2 InlineData values: InterNetwork and InterNetworkV6), suggesting only one address family variant fails per run.
    Console log example
    https://helixr1107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-heads-main-76f79e897d5246b58a/System.Net.NameResolution.Functional.Tests/1/console.858b3560.log?helixlogtype=result
    Possible fixes
    1. Fix the fallback to resolve "localhost" with AddressFamily.Unspecified and then filter results by the requested family.
    2. Investigate whether family-specific getaddrinfo("localhost", AF_INET/AF_INET6) is expected to work on Android and fix the emulator setup.
    Known issue validation
    Build: 🔎https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
    Error message validated:[LocalhostSubdomain_RespectsAddressFamily]
    Result validation: ✅ Known issue matched with the provided build.
    Validation performed at: 2/23/2026 12:30:22 PM UTC
    Report
    BuildDefinitionTestPull Request
    1408366dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
    1404759dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
    1388248dotnet/runtimeSystem.Net.NameResolution.Tests.GetHostEntryTest.Dns_GetHostEntryAsync_IPAddress_Ok#127192
    Summary
    24-Hour Hit Count7-Day Hit Count1-Month Count
    123
    Metadata
    Metadata
    Assignees
    Labels
    Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
    Type
    No type
    Projects
    No projects
      Milestone
      Relationships
      None yet
      Development
      No branches or pull requests
      Issue actions
      
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

      Skip to content
      DNS localhost subdomain tests with AddressFamily fail on Android #124751
      Closed
      #127742
      #125478
      Closed
      DNS localhost subdomain tests with AddressFamily fail on Android#124751
      #127742
      #125478
      Assignees
      simonrozsival
      Labels
      Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
      Milestone
      11.0.0
      Description
      @rzikm
      rzikm
      opened on Feb 23, 2026
      Build Information
      Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
      
Build error leg or test failing: System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily, System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily
      Error Message
      Fill the error message using step by step known issues guidance.
      {
"ErrorMessage": "LocalhostSubdomain_RespectsAddressFamily",
"ErrorPattern": "",
"BuildRetry": false,
"ExcludeConsoleLog": false
}
      Description
      The DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily and DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily tests (introduced in PR #123076 for RFC 6761 localhost subdomain handling) consistently fail on Android CI (windows.11.amd64.android.open queue).
      Error
      System.Net.Sockets.SocketException : hostname nor servname provided, or not known
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryCore(String hostName, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntry(String hostNameOrAddress, AddressFamily family)

      Analysis
      • The tests call e.g. Dns.GetHostEntry("test.localhost", AddressFamily.InterNetwork) (or InterNetworkV6).
      • The RFC 6761 implementation tries the OS resolver for "test.localhost" first, then falls back to resolving plain "localhost" with the same AddressFamily.
      • The double GetHostEntryOrAddressesCore in the stack trace confirms the fallback triggers but also fails.
      • The fallback calls getaddrinfo("localhost", ..., ai_family) with a specific address family (AF_INET or AF_INET6). On Android, this may fail (EAI_NONAME) while getaddrinfo("localhost", ..., AF_UNSPEC) succeeds.
      • Other localhost subdomain tests that use AddressFamily.Unspecified (e.g. ReturnsLoopback) pass on Android.
      • There are no non-[OuterLoop] tests that call Dns.GetHostEntry("localhost", AddressFamily.InterNetwork) directly to confirm if family-specific localhost resolution works on Android in general.
      CI Data (last 14 days, main branch)
      BuildGetHostEntry failuresGetHostAddresses failures
      130373533
      130431211
      130494322
      Each Android job has exactly 1 failure per test (the test has 2 InlineData values: InterNetwork and InterNetworkV6), suggesting only one address family variant fails per run.
      Console log example
      https://helixr1107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-heads-main-76f79e897d5246b58a/System.Net.NameResolution.Functional.Tests/1/console.858b3560.log?helixlogtype=result
      Possible fixes
      1. Fix the fallback to resolve "localhost" with AddressFamily.Unspecified and then filter results by the requested family.
      2. Investigate whether family-specific getaddrinfo("localhost", AF_INET/AF_INET6) is expected to work on Android and fix the emulator setup.
      Known issue validation
      Build: 🔎https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
      Error message validated:[LocalhostSubdomain_RespectsAddressFamily]
      Result validation: ✅ Known issue matched with the provided build.
      Validation performed at: 2/23/2026 12:30:22 PM UTC
      Report
      BuildDefinitionTestPull Request
      1408366dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
      1404759dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
      1388248dotnet/runtimeSystem.Net.NameResolution.Tests.GetHostEntryTest.Dns_GetHostEntryAsync_IPAddress_Ok#127192
      Summary
      24-Hour Hit Count7-Day Hit Count1-Month Count
      123
      Metadata
      Metadata
      Assignees
      Labels
      Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
      Type
      No type
      Projects
      No projects
        Milestone
        Relationships
        None yet
        Development
        No branches or pull requests
        Issue actions
        
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

        Skip to content
        DNS localhost subdomain tests with AddressFamily fail on Android #124751
        Closed
        #127742
        #125478
        Closed
        DNS localhost subdomain tests with AddressFamily fail on Android#124751
        #127742
        #125478
        Assignees
        simonrozsival
        Labels
        Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
        Milestone
        11.0.0
        Description
        @rzikm
        rzikm
        opened on Feb 23, 2026
        Build Information
        Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
        
Build error leg or test failing: System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily, System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily
        Error Message
        Fill the error message using step by step known issues guidance.
        {
"ErrorMessage": "LocalhostSubdomain_RespectsAddressFamily",
"ErrorPattern": "",
"BuildRetry": false,
"ExcludeConsoleLog": false
}
        Description
        The DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily and DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily tests (introduced in PR #123076 for RFC 6761 localhost subdomain handling) consistently fail on Android CI (windows.11.amd64.android.open queue).
        Error
        System.Net.Sockets.SocketException : hostname nor servname provided, or not known
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryCore(String hostName, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntry(String hostNameOrAddress, AddressFamily family)

        Analysis
        • The tests call e.g. Dns.GetHostEntry("test.localhost", AddressFamily.InterNetwork) (or InterNetworkV6).
        • The RFC 6761 implementation tries the OS resolver for "test.localhost" first, then falls back to resolving plain "localhost" with the same AddressFamily.
        • The double GetHostEntryOrAddressesCore in the stack trace confirms the fallback triggers but also fails.
        • The fallback calls getaddrinfo("localhost", ..., ai_family) with a specific address family (AF_INET or AF_INET6). On Android, this may fail (EAI_NONAME) while getaddrinfo("localhost", ..., AF_UNSPEC) succeeds.
        • Other localhost subdomain tests that use AddressFamily.Unspecified (e.g. ReturnsLoopback) pass on Android.
        • There are no non-[OuterLoop] tests that call Dns.GetHostEntry("localhost", AddressFamily.InterNetwork) directly to confirm if family-specific localhost resolution works on Android in general.
        CI Data (last 14 days, main branch)
        BuildGetHostEntry failuresGetHostAddresses failures
        130373533
        130431211
        130494322
        Each Android job has exactly 1 failure per test (the test has 2 InlineData values: InterNetwork and InterNetworkV6), suggesting only one address family variant fails per run.
        Console log example
        https://helixr1107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-heads-main-76f79e897d5246b58a/System.Net.NameResolution.Functional.Tests/1/console.858b3560.log?helixlogtype=result
        Possible fixes
        1. Fix the fallback to resolve "localhost" with AddressFamily.Unspecified and then filter results by the requested family.
        2. Investigate whether family-specific getaddrinfo("localhost", AF_INET/AF_INET6) is expected to work on Android and fix the emulator setup.
        Known issue validation
        Build: 🔎https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
        Error message validated:[LocalhostSubdomain_RespectsAddressFamily]
        Result validation: ✅ Known issue matched with the provided build.
        Validation performed at: 2/23/2026 12:30:22 PM UTC
        Report
        BuildDefinitionTestPull Request
        1408366dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
        1404759dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
        1388248dotnet/runtimeSystem.Net.NameResolution.Tests.GetHostEntryTest.Dns_GetHostEntryAsync_IPAddress_Ok#127192
        Summary
        24-Hour Hit Count7-Day Hit Count1-Month Count
        123
        Metadata
        Metadata
        Assignees
        Labels
        Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
        Type
        No type
        Projects
        No projects
          Milestone
          Relationships
          None yet
          Development
          No branches or pull requests
          Issue actions
          
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

          Skip to content
          DNS localhost subdomain tests with AddressFamily fail on Android #124751
          Closed
          #127742
          #125478
          Closed
          DNS localhost subdomain tests with AddressFamily fail on Android#124751
          #127742
          #125478
          Assignees
          simonrozsival
          Labels
          Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
          Milestone
          11.0.0
          Description
          @rzikm
          rzikm
          opened on Feb 23, 2026
          Build Information
          Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
          
Build error leg or test failing: System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily, System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily
          Error Message
          Fill the error message using step by step known issues guidance.
          {
"ErrorMessage": "LocalhostSubdomain_RespectsAddressFamily",
"ErrorPattern": "",
"BuildRetry": false,
"ExcludeConsoleLog": false
}
          Description
          The DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily and DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily tests (introduced in PR #123076 for RFC 6761 localhost subdomain handling) consistently fail on Android CI (windows.11.amd64.android.open queue).
          Error
          System.Net.Sockets.SocketException : hostname nor servname provided, or not known
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryCore(String hostName, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntry(String hostNameOrAddress, AddressFamily family)

          Analysis
          • The tests call e.g. Dns.GetHostEntry("test.localhost", AddressFamily.InterNetwork) (or InterNetworkV6).
          • The RFC 6761 implementation tries the OS resolver for "test.localhost" first, then falls back to resolving plain "localhost" with the same AddressFamily.
          • The double GetHostEntryOrAddressesCore in the stack trace confirms the fallback triggers but also fails.
          • The fallback calls getaddrinfo("localhost", ..., ai_family) with a specific address family (AF_INET or AF_INET6). On Android, this may fail (EAI_NONAME) while getaddrinfo("localhost", ..., AF_UNSPEC) succeeds.
          • Other localhost subdomain tests that use AddressFamily.Unspecified (e.g. ReturnsLoopback) pass on Android.
          • There are no non-[OuterLoop] tests that call Dns.GetHostEntry("localhost", AddressFamily.InterNetwork) directly to confirm if family-specific localhost resolution works on Android in general.
          CI Data (last 14 days, main branch)
          BuildGetHostEntry failuresGetHostAddresses failures
          130373533
          130431211
          130494322
          Each Android job has exactly 1 failure per test (the test has 2 InlineData values: InterNetwork and InterNetworkV6), suggesting only one address family variant fails per run.
          Console log example
          https://helixr1107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-heads-main-76f79e897d5246b58a/System.Net.NameResolution.Functional.Tests/1/console.858b3560.log?helixlogtype=result
          Possible fixes
          1. Fix the fallback to resolve "localhost" with AddressFamily.Unspecified and then filter results by the requested family.
          2. Investigate whether family-specific getaddrinfo("localhost", AF_INET/AF_INET6) is expected to work on Android and fix the emulator setup.
          Known issue validation
          Build: 🔎https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
          Error message validated:[LocalhostSubdomain_RespectsAddressFamily]
          Result validation: ✅ Known issue matched with the provided build.
          Validation performed at: 2/23/2026 12:30:22 PM UTC
          Report
          BuildDefinitionTestPull Request
          1408366dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
          1404759dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
          1388248dotnet/runtimeSystem.Net.NameResolution.Tests.GetHostEntryTest.Dns_GetHostEntryAsync_IPAddress_Ok#127192
          Summary
          24-Hour Hit Count7-Day Hit Count1-Month Count
          123
          Metadata
          Metadata
          Assignees
          Labels
          Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
          Type
          No type
          Projects
          No projects
            Milestone
            Relationships
            None yet
            Development
            No branches or pull requests
            Issue actions
            
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

            Skip to content
            DNS localhost subdomain tests with AddressFamily fail on Android #124751
            Closed
            #127742
            #125478
            Closed
            DNS localhost subdomain tests with AddressFamily fail on Android#124751
            #127742
            #125478
            Assignees
            simonrozsival
            Labels
            Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
            Milestone
            11.0.0
            Description
            @rzikm
            rzikm
            opened on Feb 23, 2026
            Build Information
            Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
            
Build error leg or test failing: System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily, System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily
            Error Message
            Fill the error message using step by step known issues guidance.
            {
"ErrorMessage": "LocalhostSubdomain_RespectsAddressFamily",
"ErrorPattern": "",
"BuildRetry": false,
"ExcludeConsoleLog": false
}
            Description
            The DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily and DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily tests (introduced in PR #123076 for RFC 6761 localhost subdomain handling) consistently fail on Android CI (windows.11.amd64.android.open queue).
            Error
            System.Net.Sockets.SocketException : hostname nor servname provided, or not known
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryCore(String hostName, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntry(String hostNameOrAddress, AddressFamily family)

            Analysis
            • The tests call e.g. Dns.GetHostEntry("test.localhost", AddressFamily.InterNetwork) (or InterNetworkV6).
            • The RFC 6761 implementation tries the OS resolver for "test.localhost" first, then falls back to resolving plain "localhost" with the same AddressFamily.
            • The double GetHostEntryOrAddressesCore in the stack trace confirms the fallback triggers but also fails.
            • The fallback calls getaddrinfo("localhost", ..., ai_family) with a specific address family (AF_INET or AF_INET6). On Android, this may fail (EAI_NONAME) while getaddrinfo("localhost", ..., AF_UNSPEC) succeeds.
            • Other localhost subdomain tests that use AddressFamily.Unspecified (e.g. ReturnsLoopback) pass on Android.
            • There are no non-[OuterLoop] tests that call Dns.GetHostEntry("localhost", AddressFamily.InterNetwork) directly to confirm if family-specific localhost resolution works on Android in general.
            CI Data (last 14 days, main branch)
            BuildGetHostEntry failuresGetHostAddresses failures
            130373533
            130431211
            130494322
            Each Android job has exactly 1 failure per test (the test has 2 InlineData values: InterNetwork and InterNetworkV6), suggesting only one address family variant fails per run.
            Console log example
            https://helixr1107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-heads-main-76f79e897d5246b58a/System.Net.NameResolution.Functional.Tests/1/console.858b3560.log?helixlogtype=result
            Possible fixes
            1. Fix the fallback to resolve "localhost" with AddressFamily.Unspecified and then filter results by the requested family.
            2. Investigate whether family-specific getaddrinfo("localhost", AF_INET/AF_INET6) is expected to work on Android and fix the emulator setup.
            Known issue validation
            Build: 🔎https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
            Error message validated:[LocalhostSubdomain_RespectsAddressFamily]
            Result validation: ✅ Known issue matched with the provided build.
            Validation performed at: 2/23/2026 12:30:22 PM UTC
            Report
            BuildDefinitionTestPull Request
            1408366dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
            1404759dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
            1388248dotnet/runtimeSystem.Net.NameResolution.Tests.GetHostEntryTest.Dns_GetHostEntryAsync_IPAddress_Ok#127192
            Summary
            24-Hour Hit Count7-Day Hit Count1-Month Count
            123
            Metadata
            Metadata
            Assignees
            Labels
            Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
            Type
            No type
            Projects
            No projects
              Milestone
              Relationships
              None yet
              Development
              No branches or pull requests
              Issue actions
              
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

              Skip to content
              DNS localhost subdomain tests with AddressFamily fail on Android #124751
              Closed
              #127742
              #125478
              Closed
              DNS localhost subdomain tests with AddressFamily fail on Android#124751
              #127742
              #125478
              Assignees
              simonrozsival
              Labels
              Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
              Milestone
              11.0.0
              Description
              @rzikm
              rzikm
              opened on Feb 23, 2026
              Build Information
              Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
              
Build error leg or test failing: System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily, System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily
              Error Message
              Fill the error message using step by step known issues guidance.
              {
"ErrorMessage": "LocalhostSubdomain_RespectsAddressFamily",
"ErrorPattern": "",
"BuildRetry": false,
"ExcludeConsoleLog": false
}
              Description
              The DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily and DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily tests (introduced in PR #123076 for RFC 6761 localhost subdomain handling) consistently fail on Android CI (windows.11.amd64.android.open queue).
              Error
              System.Net.Sockets.SocketException : hostname nor servname provided, or not known
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryCore(String hostName, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntry(String hostNameOrAddress, AddressFamily family)

              Analysis
              • The tests call e.g. Dns.GetHostEntry("test.localhost", AddressFamily.InterNetwork) (or InterNetworkV6).
              • The RFC 6761 implementation tries the OS resolver for "test.localhost" first, then falls back to resolving plain "localhost" with the same AddressFamily.
              • The double GetHostEntryOrAddressesCore in the stack trace confirms the fallback triggers but also fails.
              • The fallback calls getaddrinfo("localhost", ..., ai_family) with a specific address family (AF_INET or AF_INET6). On Android, this may fail (EAI_NONAME) while getaddrinfo("localhost", ..., AF_UNSPEC) succeeds.
              • Other localhost subdomain tests that use AddressFamily.Unspecified (e.g. ReturnsLoopback) pass on Android.
              • There are no non-[OuterLoop] tests that call Dns.GetHostEntry("localhost", AddressFamily.InterNetwork) directly to confirm if family-specific localhost resolution works on Android in general.
              CI Data (last 14 days, main branch)
              BuildGetHostEntry failuresGetHostAddresses failures
              130373533
              130431211
              130494322
              Each Android job has exactly 1 failure per test (the test has 2 InlineData values: InterNetwork and InterNetworkV6), suggesting only one address family variant fails per run.
              Console log example
              https://helixr1107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-heads-main-76f79e897d5246b58a/System.Net.NameResolution.Functional.Tests/1/console.858b3560.log?helixlogtype=result
              Possible fixes
              1. Fix the fallback to resolve "localhost" with AddressFamily.Unspecified and then filter results by the requested family.
              2. Investigate whether family-specific getaddrinfo("localhost", AF_INET/AF_INET6) is expected to work on Android and fix the emulator setup.
              Known issue validation
              Build: 🔎https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
              Error message validated:[LocalhostSubdomain_RespectsAddressFamily]
              Result validation: ✅ Known issue matched with the provided build.
              Validation performed at: 2/23/2026 12:30:22 PM UTC
              Report
              BuildDefinitionTestPull Request
              1408366dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
              1404759dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
              1388248dotnet/runtimeSystem.Net.NameResolution.Tests.GetHostEntryTest.Dns_GetHostEntryAsync_IPAddress_Ok#127192
              Summary
              24-Hour Hit Count7-Day Hit Count1-Month Count
              123
              Metadata
              Metadata
              Assignees
              Labels
              Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
              Type
              No type
              Projects
              No projects
                Milestone
                Relationships
                None yet
                Development
                No branches or pull requests
                Issue actions
                
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

                Skip to content
                DNS localhost subdomain tests with AddressFamily fail on Android #124751
                Closed
                #127742
                #125478
                Closed
                DNS localhost subdomain tests with AddressFamily fail on Android#124751
                #127742
                #125478
                Assignees
                simonrozsival
                Labels
                Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
                Milestone
                11.0.0
                Description
                @rzikm
                rzikm
                opened on Feb 23, 2026
                Build Information
                Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
                
Build error leg or test failing: System.Net.NameResolution.Tests.GetHostEntryTest.DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily, System.Net.NameResolution.Tests.GetHostAddressesTest.DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily
                Error Message
                Fill the error message using step by step known issues guidance.
                {
"ErrorMessage": "LocalhostSubdomain_RespectsAddressFamily",
"ErrorPattern": "",
"BuildRetry": false,
"ExcludeConsoleLog": false
}
                Description
                The DnsGetHostEntry_LocalhostSubdomain_RespectsAddressFamily and DnsGetHostAddresses_LocalhostSubdomain_RespectsAddressFamily tests (introduced in PR #123076 for RFC 6761 localhost subdomain handling) consistently fail on Android CI (windows.11.amd64.android.open queue).
                Error
                System.Net.Sockets.SocketException : hostname nor servname provided, or not known
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntryCore(String hostName, AddressFamily addressFamily, ...)
at System.Net.Dns.GetHostEntry(String hostNameOrAddress, AddressFamily family)

                Analysis
                • The tests call e.g. Dns.GetHostEntry("test.localhost", AddressFamily.InterNetwork) (or InterNetworkV6).
                • The RFC 6761 implementation tries the OS resolver for "test.localhost" first, then falls back to resolving plain "localhost" with the same AddressFamily.
                • The double GetHostEntryOrAddressesCore in the stack trace confirms the fallback triggers but also fails.
                • The fallback calls getaddrinfo("localhost", ..., ai_family) with a specific address family (AF_INET or AF_INET6). On Android, this may fail (EAI_NONAME) while getaddrinfo("localhost", ..., AF_UNSPEC) succeeds.
                • Other localhost subdomain tests that use AddressFamily.Unspecified (e.g. ReturnsLoopback) pass on Android.
                • There are no non-[OuterLoop] tests that call Dns.GetHostEntry("localhost", AddressFamily.InterNetwork) directly to confirm if family-specific localhost resolution works on Android in general.
                CI Data (last 14 days, main branch)
                BuildGetHostEntry failuresGetHostAddresses failures
                130373533
                130431211
                130494322
                Each Android job has exactly 1 failure per test (the test has 2 InlineData values: InterNetwork and InterNetworkV6), suggesting only one address family variant fails per run.
                Console log example
                https://helixr1107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-heads-main-76f79e897d5246b58a/System.Net.NameResolution.Functional.Tests/1/console.858b3560.log?helixlogtype=result
                Possible fixes
                1. Fix the fallback to resolve "localhost" with AddressFamily.Unspecified and then filter results by the requested family.
                2. Investigate whether family-specific getaddrinfo("localhost", AF_INET/AF_INET6) is expected to work on Android and fix the emulator setup.
                Known issue validation
                Build: 🔎https://dev.azure.com/dnceng-public/public/_build/results?buildId=1304943
                Error message validated:[LocalhostSubdomain_RespectsAddressFamily]
                Result validation: ✅ Known issue matched with the provided build.
                Validation performed at: 2/23/2026 12:30:22 PM UTC
                Report
                BuildDefinitionTestPull Request
                1408366dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
                1404759dotnet/runtimeSystem.Net.NameResolution.Functional.Tests.WorkItemExecution
                1388248dotnet/runtimeSystem.Net.NameResolution.Tests.GetHostEntryTest.Dns_GetHostEntryAsync_IPAddress_Ok#127192
                Summary
                24-Hour Hit Count7-Day Hit Count1-Month Count
                123
                Metadata
                Metadata
                Assignees
                Labels
                Known Build ErrorUse this to report build issues in the .NET Helix tabarea-System.Netdisabled-testThe test is disabled in source code against the issueos-android
                Type
                No type
                Projects
                No projects
                  Milestone
                  Relationships
                  None yet
                  Development
                  No branches or pull requests
                  Issue actions