AppGW is a PaaS instance , by default you wont get access to the Applicaiton Gateway. On the Export File Format page, select Base-64 encoded X.509 (.CER)., and then click Next. Hope this helps. @einarasm read thru the responses from @krish-gh, specifically around leveraging OpenSSL toolkit to query the backend pool for the certificate trust chain, example: %> openssl s_client -connect 10.0.0.4:443 -servername www.example.com -showcerts. Otherwise, it will be marked as Unhealthy with this message. -No client certificate CA names sent Sure I would be glad to get involved if needed. Cause: If the backend pool is of type IP Address, FQDN or App Service, Application Gateway resolves to the IP address of the FQDN entered through DNS (custom or Azure default). to your account. EDIT: Turned out I uploaded wrong pfx compared to the backend server. "Backend server certificate is not whitelisted with Application Gateway." Something that you will see missing is microsft docs is having a default site binding to a SSL certificate without the SNI enabled. 10.0.0.4 = IP of backend server (if using DNS ensure it points to backend server and not the public IP of appgw). Cause: End-to-end SSL with Application Gateway v2 requires the backend server's certificate to be verified in order to deem the server Healthy. Below is what happens during SSL negotiation when you have single chain cert and root in the AppGW. It seems like something changed on the app gateway starting this month. @sajithvasu I would continue to work with the support engineers while they look deeper into your authentication certificate. Alternatively, you can export the root certificate from a client machine by directly accessing the server (bypassing Application Gateway) through browser and exporting the root certificate from the browser. Just FYI. same situation as @JeromeVigne: App Gateway v1 as front-end to API Management, the health probe is unhealthy with the "Backend server certificate is not whitelisted with Application Gateway . Nice article mate! If you are not familiar with Cloud Shell, it allows you to access bash or powershell from your browser to run commands within your Azure subscription https://docs.microsoft.com/en-us/azure/cloud-shell/overview. error. How to connect to new Wi-Fi in Windows 11? If you open your certificate with Notepad and it doesn't look similar to this, typically this means you didn't export it using the Base-64 encoded X.509(.CER) format. Open the Application Gateway HTTP Settings page in the Azure portal. @EmreMARTiN you can run openssl from your local machine pointing to your backend, not external over WAF. Check whether your UDR has a default route (0.0.0.0/0) with the next hop not set as Internet: a. For new setup, we have noticed that app gateway back-end becomes unhealthy. Visual Studio Code How to Change Theme ? b. An authentication certificate is required to allow backend instances in Application Gateway v1 SKU. b. Our configuration is similar to this article but we are using WAF V1 sku - https://www.domstamand.com/end-to-end-ssl-solution-using-web-apps-and-azure-application-gateway-multisite-hosting/ If you're aware of the application's behavior and it should respond only after the timeout value, increase the timeout value from the custom probe settings. @JeromeVigne did you find a solution in your setup? To troubleshoot this issue, check the Details column on the Backend Health tab. Hi @TravisCragg-MSFT : Were you able to check this? If your certificate is working on browser directly hitting the app and not with AppGW then what is the exact problem? Cause: After the TCP connection has been established and a TLS handshake is done (if TLS is enabled), Application Gateway will send the probe as an HTTP GET request to the backend server. Follow steps 1-10 in the preceding section to upload the correct trusted root certificate to Application Gateway. Document Details This is the exact thing what we do when import .CER file in the HTTP Settings of the Application Gateway. #please-close. Sorry my bad, this is actually now working - I just needed to have the CN in the certificate match with what was set in backend pool. I just set it up and cannot get the health probe for HTTPS healthy. Set the destination port as anything, and verify the connectivity. @EmreMARTiN , you mentioned your backend certificate is from "Digicert" which is already a well-known trusted CA. or from external over WAF ? Make sure the UDR isn't directing the traffic away from the backend subnet. b. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. My issue was due to the root certificate not being presented to appgw, and resulted in the error: "The root certificate of the server certificate used by the backend does not match the trusted root certificate added to the application gateway. Select the setting that has the expired certificate, select, The NSG on the Application Gateway subnet is blocking inbound access to ports 65503-65534 (v1 SKU) or 65200-65535 (v2 SKU) from Internet. certificate. -Verify return code: 19 (self signed certificate in certificate chain). Ensure that you add the correct root certificate to whitelist the backend. Ensure that you add the correct root certificate to allowlist the backend. Is there such a thing as "right to be heard" by the authorities? respond within the configured period (the timeout value), it's marked as Unhealthy until it starts responding within the configured timeout period again. Connect and share knowledge within a single location that is structured and easy to search. This error can also occur if the backend server doesn't exchange the complete chain of the cert, including the Root > Intermediate (if applicable) > Leaf during the TLS handshake. We have not faced any issues with HTTP sites but we are facing issues with end-to-end SSL. Ensure that you add the correct root certificate to whitelist the backend". The text was updated successfully, but these errors were encountered: @sajithvasu I am not aware of any changes that have been made on the App Gateway side that would make this not work. Required fields are marked *. We are actually trying to simulate the Linux box as AppGW. When i check health probe details are following: My issue was due to the root certificate not being presented to appgw, and resulted in the error: "The root certificate of the server certificate used by the backend does not match the trusted root certificate added to the application gateway. The current data must be within the valid from and valid to range. More info about Internet Explorer and Microsoft Edge, https://learn.microsoft.com/en-us/azure/application-gateway/application-gateway-backend-health-troubleshooting, https://learn.microsoft.com/en-us/azure/application-gateway/certificates-for-backend-authentication#export-trusted-root-certificate-for-v2-sku, https://learn.microsoft.com/en-us/azure/application-gateway/ssl-overview#end-to-end-tls-with-the-v2-sku. Is that we have to follow the below step for resolution ? The authentication certificate is the public key of backend server certificates in Base-64 encoded X.509(.CER) format. If your backend is within a VNET not accessible from your local, the you run openssl from a Cloud Shell within VNET. -> Same certificate with private key from applicaton server. Unfortunately I have to use the v1 for this set-up. If the output doesnt show the complete chain of the certificate being returned, export the certificate again with the complete chain, including the root certificate. Ended up swapping to App Gateway V2 instead using the Trusted CA cert option on the backend http settings. Parabolic, suborbital and ballistic trajectories all follow elliptic paths. The intermediate certificate(s) should be bundled with server certificate and installed on the backend server. If the certificate wasn't issued by a trusted CA (for example, a self-signed certificate was used), users should upload the issuer's certificate to Application Gateway. Access the backend server directly and check the time taken for the server to respond on that page. This will take some time to track down, fix, and the docs will need to be updated with limitations & best practices. Azure Application Gateway "502 Web Server" - Backend Certificate not Please upload a valid certificate, Azure Application Gateway - check health on subset of backend nodes, Certificate error Azure Application Gateway, Azure Application gateway health check certificate mismatch, Azure Application Gateway Backend Setting Certificate error - ApplicationGatewayTrustedRootCertificateInvalidData, Redirect traffic of Azure Application Gateway based on health probe. Trusted root certificate is required to allow backend instances in application gateway v2 SKU. security issue in which Application Gateway marks the backend server as Unhealthy. c. If the next hop is virtual network gateway, there might be a default route advertised over ExpressRoute or VPN. Check the backend server's health and whether the services are running. Find centralized, trusted content and collaborate around the technologies you use most. For example, you can configure Application Gateway to accept "unauthorized" as a string to match. The issue was on certificate. Expected:{HTTPStatusCode0} Received:{HTTPStatusCode1}. I have some questions in regards to application gateway and need help with the same : 1)Is that application gateway can be configured with multiple backend pools and each pool can serve a request for different applications ? The reason why I try to use CA cert is that I manage all the resource in terraform, with a single CA cert, it is better to automate the process. I will post any updates here as soon as I have them. If Internet and private traffic are going through an Azure Firewall hosted in a secured Virtual hub (using Azure Virtual WAN Hub): a. Something that you will see missing is microsft docs is having a default site binding to a SSL certificate without the SNI enabled. Azure Tip #11 Get Reports of ARM Deployments in Your Subscription. Azure Tip #7 What are the Storage Tiers in Azure ? I have created an application gateway with 3 backend nodes, when I set the "Http Listener" with all the 3 nodes certificates, the health probe is green. An authentication certificate is required to allow backend instances in Application Gateway v1 SKU. You can find this by running openssl from either windows client or Linux client which is present in the same network/subnet of the backend application. Open a command prompt (Win+R -> cmd), enter netstat, and select Enter. There is ROOT certificate on httpsettings. Let me set the scene. Because the probe requests don't carry any user credentials, they will fail, and an HTTP 401 status code will be returned by the backend server. This is the exact thing what we do when import .CER file in the HTTP Settings of the Application Gateway. It worked fine for me with the new setup in the month of September with V1 SKU.