aspnet: note on proxy ip (#4892)

* aspnet: note on proxy ip

* Update src/platforms/dotnet/common/troubleshooting.mdx

Co-authored-by: Isabel <[email protected]>

* add missing period

Co-authored-by: Matt Johnson-Pint <[email protected]>
Co-authored-by: Isabel <[email protected]>

Author: 3 people

src/platforms/dotnet/common/troubleshooting.mdx

@@ -4,4 +4,11 @@ sidebar_order: 100
 description: "Learn more about how to troubleshoot common issues with the .NET SDK. "
 ---
 
+## User IP address in Sentry shows up as the server IP
+
+If you're using a proxy server that relies on `X-Forwarded-For`, you might need to [configure ASP.NET Core
+so that it's aware of it](https://docs.microsoft.com/aspnet/core/host-and-deploy/proxy-load-balancer).
+
+See [this GitHub issue] (https://github.com/getsentry/sentry-dotnet/issues/258) for more context.
+
 <PlatformContent includePath="troubleshooting" />