Using non standard port-80 and 443 for Azure Application Proxy

Question

Good day,

We have an internal webserver which hosts two WebApplications.

The first app runs on port 443 and the second one on 449.

My problem is with the second app when using an Entra Enterprise app, the first app runs fine.

I am using a AAD Proxy.

Internal url : https://mydomain.we.net:449/myapp02/

External url : https://mydomain.we.net/myapp02/

On the Azure Proxy connector VM (on-premise) i can access the app on 449. So internally there is not connection issues nor dns issues.

But externally it begins to load the page ( which means the proxy is replying to the client browser) then i get all kinds of erros

https://mydomain.we.net:449/myapp02/ net::ERR_CONNECTION_TIMED_OUT

and Fail to load resource: net::ERR_CONNECTION_TIMED_OUT

It seems my application communicates back on 449, as the proxy and connector reverts back only on port 80 and 443 i get those errors. Help would be appreciated.

Answer 1

Hi there and thank you for reaching out to the Q & A community.

Please correct me if I'm wrong.

From your description it sounds like the first app running on 443 is trying to redirect to the 2nd app running on port 449.

If this is it the case then you may be able to get around this by using Link translation.

https://learn.microsoft.com/en-us/entra/identity/app-proxy/application-proxy-configure-hard-coded-link-translation#how-link-translation-works

If your application is redirecting using hard coded urls generated through javascript link translation is not supported.

Steps to use link translation:

• Ensure each application is published using app proxy. App 1 will have internal and external urls going to 443. https://mydomain.we.net/myapp02/ App 2 will have internal url going to https://mydomain.we.net:449/myapp02/ and external going to https://mydomain.we.net/
• In your app proxy settings please ensure that translate urls in headers and body are checked.

If the steps above were able to help you please accept this answer or if my understanding of your scenario is incorrect please let me know how you have configured both applications through app proxy.

How are you accessing the application working on 449? is it directly through app proxy or is the first app redirecting the 2nd app?