When testing the latest version of a docker image for an <a href="http://ASP.NET" class="autolinkedURL autolinkedURL-url" target="_blank">ASP.NET</a> Core API the request sent never received a response when testing with Postman.
<pre><code class="lang-sh">Error: Exceeded maxRedirects. Probably stuck in a redirect loop https://somesite.azurewebsites.net/route
</code></pre>
Checking the logstream:
<pre><code class="lang-sh">2021-02-23T00:12:45.373140644Z: [INFO] [40m[32minfo[39m[22m[49m: Microsoft.AspNetCore.Hosting.Diagnostics[2]
2021-02-23T00:12:45.373144644Z: [INFO] Request finished in 0.5084ms 307
</code></pre>
The 307 HTTP status code is a redirect. 
Looking at the code we have a UseHttpsRedirection in the Configure method in Startup.cs:
<pre><code class="lang-csharp">app.UseHttpsRedirection();
</code></pre>
There was no configuration in the ConfigureServices method such as:
<pre><code class="lang-csharp">services.AddHttpsRedirection(options =&gt;
{
 options.HttpsPort = 443;
});
</code></pre>
Note, I also added the above option to ConfigureServices and specified ASPNETCORE_HTTPS_PORT to 443. As well as port 80 for both to no avail.
This service was originally used with an IIS Reverse Proxy. After removing the UseHttpsRedirection, I was able to get a 200 status code back. I've followed the guidelines to enable the HTTPS Only option under the service app's TLS/SSL settings.
References
<ul>
<li><a href="https://github.com/dotnet/aspnetcore/issues/3176" class="autolinkedURL autolinkedURL-url" target="_blank">github.com/dotnet/aspnetcore/issues/3176</a></li>
<li><a href="https://stackoverflow.com/questions/60430781/unable-to-start-kestrel-on-azure-app-services-throws-unable-to-configure-https-e" class="autolinkedURL autolinkedURL-url" target="_blank">stackoverflow.com/questions/60430781/unable..</a></li>
</ul>

When testing the latest version of a docker image for an ASP.NET Core API the request sent never received a response when testing with Postman.

```sh
Error: Exceeded maxRedirects. Probably stuck in a redirect loop https://somesite.azurewebsites.net/route
```

Checking the logstream:
```sh
2021-02-23T00:12:45.373140644Z: [INFO]  [40m[32minfo[39m[22m[49m: Microsoft.AspNetCore.Hosting.Diagnostics[2]
2021-02-23T00:12:45.373144644Z: [INFO]        Request finished in 0.5084ms 307 
```

The 307 HTTP status code is a redirect. 

Looking at the code we have a UseHttpsRedirection in the Configure method in Startup.cs:
```csharp
app.UseHttpsRedirection();
```

There was no configuration in the ConfigureServices method such as:

```csharp
services.AddHttpsRedirection(options =>
{
   options.HttpsPort = 443;
});
```

Note, I also added the above option to ConfigureServices and specified ASPNETCORE_HTTPS_PORT to 443.  As well as port 80 for both to no avail.

This service was originally used with an IIS Reverse Proxy.  After removing the UseHttpsRedirection, I was able to get a 200 status code back.  I've followed the guidelines to enable the HTTPS Only option under the service app's TLS/SSL settings.



**References**
* https://github.com/dotnet/aspnetcore/issues/3176
* https://stackoverflow.com/questions/60430781/unable-to-start-kestrel-on-azure-app-services-throws-unable-to-configure-https-e

Azure Web App for Containers, Kestrel, and UseHttpsRedirection

I am a developer in Seattle with interests in Security (cyber and IRL), machine learning, and distributed systems.  The best practice is doing.  Teaching is learning.
