edit asp0028 /1

aspnetcore/diagnostics/asp0028.md

@@ -17,11 +17,17 @@ uid: diagnostics/asp0028
 
 ## Cause
 
-On the server machine that supports IPv6, listening to `Any`, rather than `IPv6Any` will either not work or be slower than necessary, because of the [underlying System types implementation](https://github.com/dotnet/runtime/issues/82404).
+[IPv6Any](/dotnet/api/system.net.ipaddress.ipv6any) is preferred to [Any](/dotnet/api/system.net.ipaddress.any) because `Any` is less performant than `IPv6Any`. In some cases, `Any` may not work at all. `Any` has performance problems due to the [underlying System types implementation](https://github.com/dotnet/runtime/issues/82404).
 
-At the moment of current article publishing, in case of HTTP/1.x or HTTP/2.0 a name like `localhost` will resolve to `[::1]`, which won't be accepted by the server, forcing a retry with `127.0.0.1` (i.e. failed attempt before each connection).
+`127.0.0.1` is the IPv4 loopback address. `::1` is the IPv6 loopback address. `Any` is the wildcard address for IPv4. `IPv6Any` is the wildcard address for IPv6.
+
+Current behavior with with IPv6 when using  HTTP/1.x or HTTP/2.0:
+
+* `localhost` resolves to `[::1]`.
+* `[::1]` isn't accepted by the server, which forces a retry using `127.0.0.1`, creating a repeated cycle.
+
+Using `Any` with the preceding conditions reports the `ASP0028` diagnostic message:
 
-This usage will be reported with a diagnostic message:
 ```csharp
 .UseKestrel().ConfigureKestrel(options =>
 { 
@@ -31,36 +37,32 @@ This usage will be reported with a diagnostic message:
 
 ## Rule description
 
-The recommended way is to setup Kestrel to listen on `IPv6Any`.
+The recommended way to configure Kestrel to listen for incoming connections on all available `IPv6` network interfaces is with `IPv6Any`.
 
 ## How to fix violations
 
-For the reported code
-```csharp
-.UseKestrel().ConfigureKestrel(options =>
-{ 
-    options.Listen(IPAddress.Any, ...);
-})
-```
+For the problematic code, replace `Any` with `IPv6Any`:
 
-One can either explicitly change usage to `IPv6Any`:
-```csharp
+```diff
 .UseKestrel().ConfigureKestrel(options =>
 { 
-    options.Listen(IPAddress.IPv6Any, ...);
+-   options.Listen(IPAddress.Any, ...);
++   options.Listen(IPAddress.IPv6Any, ...);
 })
 ```
 
-or use another invocation - `options.ListenAnyIP()` without specifying any argument explicitly:
-```csharp
+Alternatively, use the [ListenAnyIP](https://source.dot.net/#Microsoft.AspNetCore.Server.Kestrel.Core/KestrelServerOptions.cs,1c84a7db2c1f6892) method without specifying any arguments:
+
+```diff
 .UseKestrel().ConfigureKestrel(options =>
 { 
-    options.ListenAnyIP(...);
+-   options.Listen(IPAddress.Any, ...);
++   options.ListenAnyIP(...);
 })
 ```
 
 ## When to suppress warnings
 
-The severity level of this diagnostic is Information. You can suppress warnings if your intention is to disable `IPv6` usage completely on the server. 
+The `ASP0028` diagnostic has [Information](/dotnet/api/microsoft.extensions.logging.loglevel) level severity. Suppress this warning if your intention is to disable `IPv6` usage completely on the server, although doing so risks the performance problems mentioned in this article.
 
-You can disable IPv6 either system-wide, or for .NET only via the [AppCtx switch or environment variable](https://devblogs.microsoft.com/dotnet/dotnet-6-networking-improvements/#an-option-to-globally-disable-ipv6)
+`IPv6` can be disabled either system-wide, or for .NET only via the [AppCtx switch or environment variable](https://devblogs.microsoft.com/dotnet/dotnet-6-networking-improvements/#an-option-to-globally-disable-ipv6)

aspnetcore/toc.yml

@@ -1301,6 +1301,8 @@ items:
         uid: diagnostics/asp0025
       - name: ASP0026
         uid: diagnostics/asp0026
+      - name: ASP0028
+        uid: diagnostics/asp0028
       - name: BL0001
         uid: diagnostics/bl0001
       - name: BL0002