How to fix the path based routing in application gateway

Question

How to fix the path based routing in application gateway

George Mathews 0

Hi Q/A Team,

I have configured two ubuntu servers and added embed code in the html one is image embed code and other one is youtube embed code so i have created application gateway loadbalancer for path based routing so I have configured all the backend pools, routing rules and health probes as well and both backend health status are healthy so the challenging thing is when i try to browse with loadbalancer ip with the path I'm getting error that 404 not found. how to overcome this issue.

Rohith Vinnakota 4,010 Reputation points Microsoft External Staff

2025-04-18T17:50:30.64+00:00
Hi @George Mathews

A 404 error typically indicates that the server couldn't find the requested resource at the specified path. Since you've set up path-based routing with an application gateway and both backend health statuses are showing as healthy, here are a few steps you can take to troubleshoot and resolve the issue:

Double-check the routing rules in your application gateway configuration. Ensure that the paths you’ve defined (e.g., /images/ or /youtube/) match the paths in your backend servers’ content.

On your Ubuntu servers, confirm that the HTML files (with the image embed and YouTube embed) are served at the expected paths.

For example, if the path is /images/, ensure that the file structure and web server configuration on the backend server allow access to this path

In the meantime, you can also access the backend using the same path.

Kindly let us know if the above helps or you need further assistance on this issue.
George Mathews 0 Reputation points

2025-04-20T09:45:08.7033333+00:00

Dear @Rohith Vinnakota ,Issue not resolved still the same even though i have tried above suggestions.
Rohith Vinnakota 4,010 Reputation points Microsoft External Staff

2025-04-21T18:03:27.4833333+00:00

Hello @George Mathews

I have sent a message in the private message. Could you please share those details?

2 answers

Your answer

Rohith Vinnakota 4,010 Reputation points Microsoft External Staff

2025-04-18T17:50:30.64+00:00

Hi @George Mathews

A 404 error typically indicates that the server couldn't find the requested resource at the specified path. Since you've set up path-based routing with an application gateway and both backend health statuses are showing as healthy, here are a few steps you can take to troubleshoot and resolve the issue:

Double-check the routing rules in your application gateway configuration. Ensure that the paths you’ve defined (e.g., /images/ or /youtube/) match the paths in your backend servers’ content.

On your Ubuntu servers, confirm that the HTML files (with the image embed and YouTube embed) are served at the expected paths.

For example, if the path is /images/, ensure that the file structure and web server configuration on the backend server allow access to this path

In the meantime, you can also access the backend using the same path.

Kindly let us know if the above helps or you need further assistance on this issue.
George Mathews 0 Reputation points

2025-04-20T09:45:08.7033333+00:00

Dear @Rohith Vinnakota ,Issue not resolved still the same even though i have tried above suggestions.
Rohith Vinnakota 4,010 Reputation points Microsoft External Staff

2025-04-21T18:03:27.4833333+00:00

Hello @George Mathews

I have sent a message in the private message. Could you please share those details?

Answer 1

Hi @George Mathews,

Please verify that the path patterns in your Application Gateway routing rules match the actual content served by your backend servers. For example, if the rule is /images/*, your server should serve content like /images/index.html.

Additionally, log in to both Ubuntu VMs and check whether the corresponding folders exist using the appropriate commands.

sudo ls /var/www/html/images/
sudo ls /var/www/html/youtube/

User's image For testing, try accessing the application directly from the backend VM's public IP and check whether you're able to reach the content successfully

http://<backend-ip>/images/
http://<backend-ip>/youtube/

Check the local firewall ports using the cmdlet below.

sudo ufw status verbose

If the firewall is enabled, make sure to allow port 80 using the cmdlet below

sudo ufw allow 80

To enable UFW (if needed): sudo ufw enable

If you are able to access the application using the VM's public IP, please verify the path-based settings in the application gateway's backend target configuration.

User's image

And also check the backend settings configuration.

User's image

**Health Probe settings
**
User's image

[http://172.212.65.134/images/ ]

[[http://172.212.65.134/youtube/]]

Here is my result of images server and YouTube.

User's image

Reference: https://learn.microsoft.com/en-us/azure/application-gateway/create-url-route-portal#configuration-tab

I hope this is helpful! Do not hesitate to let me know if you have any other questions.

I really appreciate your feedback. It’s valuable to us. Please click Accept Answer on this post to assist other community members facing similar issues in finding the correct solution

Venkat V 1,485 Reputation points Microsoft External Staff

2025-04-24T05:37:27.2366667+00:00

Hi @George Mathews,

I just wanted to follow up and see if you had a chance to review my response to your question. Please let us know if it was helpful, and feel free to reach out if you have any further queries.

Answer 2

Hi @George Mathews ,

Regarding you configuration you mentioned - both backend health status is healthy.

Can you kindly confirm if you are using default health probe or custom health probe.

If you are using the correct health probe configuration then even health probe as shown in the below image then then probe would be unhealthy as the backend server is giving 404 statuses as 404 by default comes under unhealthy status.

User's image

In addition to Venkat's answer if your backend VM does not have public ip address, you can try to access server 1 from server 2 and vice versa.

http://<Server1>/images/
http://<Server1>/youtube/

If those return 404, the issue is with the web server configuration, not the application gateway. Anyway, i will wait for your response.

Regards

Ujjawal Tyagi

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How to fix the path based routing in application gateway

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