Front Door keeps domain name not like VM's IP

Question

Hello. I wanna make these functions.

I've already done this.

1. When I enter the URL I was gotten from Azure FrontDoor like something-azurefd.net , It redirects users to virtual machine's IP in my origin group.
2. Each virtual machines are deploying webservice by nginx
3. I used FrontDoor as Load balancer.

I wanna make this.

1. When Front Door redirects to IP address, User see something-azurefd.net not like IP address. I mean It keep shows it's domain name.

Additional Info:

I am currently utilizing Azure Front Door to distribute traffic across three VMs, each running a web service with Nginx and the Laravel framework. When I access the service through the provided azurefd.net domain from Azure Front Door, the traffic is correctly distributed to the backend servers. However, I don't want a specific server's IP address to be exposed in the browser's address bar. Regardless of which backend server is serving the request, I wish for the URL to always appear as azurefd.net/any/path. Please guide me on any configurations or settings that might achieve this desired behavior.

So far, I've undertaken the following actions:

• Nginx Configuration Check: There are no settings related to redirects, returns, or rewrites.
• Laravel .env Modification: I've set the APP_URL to http://myazurefd.azurefd.net.
• PHP app.php Modification: I've updated the 'url' setting to env('APP_URL', 'http://myazurefd.azurefd.net').

Despite these changes, the issue remains unresolved. Is it possible for using custom domains only?

Answer 1

Hello @Matthew Jung ,

I understand that you've configured an Azure Front Door with backend virtual machines and when you try to access the default frontend host of your Azure Front Door, it redirects to the backend VM's IP address.

I requested you to share the screenshots of your configuration for further investigation and I setup a lab with Azure Front Door Standard and a backend VM behind it with similar settings as you and it worked fine without exposing the backend VM IP.

But in your case, I see the Front Door URL is receiving a HTTP 302 redirect response as below:

And you can see the location header, where the redirects being sent from the app are using the ip address/login URL, and not a request path or the frontend hostname of your Azure Front door.

This means that any time you are redirected via a 302 status using a location header, your browser will be requesting to connect directly to the backend rather than having the front door act as a reverse proxy.

This is due to "Absolute URL redirects," where the server (backend VM in this case) sends the client a full URL in the location header rather than just a request path, which is called a "Relative URL redirect."

According to https://www.seoclarity.net/resources/knowledgebase/difference-relative-absolute-url-15325/

An absolute URL contains the entire address from the protocol (HTTPS) to the domain name (www.example.com ) and includes the location within your website in your folder system (/foldernameA or /foldernameB) names within the URL.

The relative URL, on the other hand, does not use the full web address and only contains the location following the domain. It assumes that the link you add is on the same site and is part of the same root domain.

To fix this, you could do one of the following:

• Add Custom Domain. Refer: https://learn.microsoft.com/en-us/azure/frontdoor/standard-premium/how-to-add-custom-domain
• Change code of app. Refer: [http://nginx.org/en/docs/http/ngx_http_sub_module.html]

Could you please check this redirect in your application and try to fix the code?

If not possible, then the only way is to use custom domain in this case.

Kindly let us know if the above helps or you need further assistance on this issue.

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