Configure that certificate on your backend server. You can add this github issue reference in your ticket so that the Azure support personnel can see the details without asking you to repeat these steps. Which language's style guidelines should be used when writing code that is supposed to be called from another language? Message: Body of the backend's HTTP response did not match the I am currently experimenting with different ways to add the backend pools and heath probes to find a working configuration. Already on GitHub? If your cert is issued by Internal Root CA , you would have export the root cert and import it the Trust Root Store in the Client. But if this message is displayed, it suggests that Application Gateway couldn't successfully resolve the IP address of the FQDN entered. c. Check the user-defined routes (UDR) settings of Application Gateway and the backend server's subnet for any routing anomalies. Have a question about this project? 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. There is ROOT certificate on httpsettings. The section in blue contains the information that is uploaded to application gateway. Is there such a thing as "right to be heard" by the authorities? Azure Applicaiton Gateway V2 Certification Issue #62578 - Github For example, check for routes to network virtual appliances or default routes being advertised to the Application Gateway subnet via Azure ExpressRoute and/or VPN. One pool has 2 servers listed as unhealthy and the error message we see is below: "backend server certificate is not whitelisted with application gateway .Make sure that the certificate uploaded to the application gateway matches with the certificate configured in the backend servers. The text was updated successfully, but these errors were encountered: @EmreMARTiN, Thanks for the feedback. Let me set the scene. The root certificate is a Base-64 encoded X.509(.CER) format root certificate from the backend server certificates. Solution: If you receive this error message, there's a mismatch between the certificate that has been uploaded to Application Gateway and the one that was uploaded to the backend server. We have this setup in multiple places created last year and it all works fine. In this article I am going to talk about one most common issue "backend certificate not whitelisted" How to Allow or Prevent Themes to Change Desktop Icons in Desktop Icon Settings in Windows 11? Can you recreate this scenario in your lab using multi-site and custom domain on appservices with SNI bind SSL and cert issued by different CA than Microsoft and not the default azurewebsites.net and you may hit this issue? Message: The root certificate of the server certificate used by the backend does not match the trusted root certificate added to the application gateway. I have the same issue, Root cert is DigiCert. b. SAP on Azure: Azure Application Gateway Web Application Firewall (WAF Now Clients will check the Server certificate and confirm if the certificate is issued by Trusted root or not. Azure Application Gateway "502 Web Server" - Backend Certificate not Certificates required to allow backend servers - Azure Application Gateway In the Certificate properties, select the Details tab. Configure that certificate on your backend server. Follow steps 1-10 in the preceding section to upload the correct trusted root certificate to Application Gateway. Solution: Follow these steps to export and upload the trusted root certificate to Application Gateway. The default probe request is sent in the format of ://127.0.0.1:. Solution: To resolve this issue, verify that the certificate on your server was created properly. In this example, you'll use a TLS/SSL certificate for the backend certificate and export its public key to be used as . Create a free website or blog at WordPress.com. Trusted root certificate is required to allow backend instances in application gateway v2 SKU. If the null hypothesis is never really true, is there a point to using a statistical test without a priori power analysis? Check whether the host name path is accessible on the backend server. Connect and share knowledge within a single location that is structured and easy to search. Client has renewed cert which is issued by GlobalSign and one of the listeners started to fail with same error. How to Change Network Location to Private, Public, or Domain in Windows 11? The exported certificate looks similar to this: If you open the exported certificate using Notepad, you see something similar to this example. Choose the destination manually as any internet-routable IP address like 1.1.1.1. At the time of writing the Application Gateway doesnt support uploading the Certificates directly into Key Vault, hence extracting the string into .txt and dumping it in Key Vault Secrets. The following steps help you export the .cer file for your certificate: Use the steps 1 - 8 mentioned in the previous section Export authentication certificate (for v1 SKU) to export the public key from your backend certificate. Sign in When calculating CR, what is the damage per turn for a monster with multiple attacks? @sajithvasu This lab takes quite a long time to set up! @JeromeVigne did you find a solution in your setup? backend server, it waits for a response from the backend server for a configured period. Azure Application Gateway Backend Certificate not whitelisted Error @TravisCragg-MSFT: I have same configuration on different places which were built a while ago and those are perfectly working fine. Configure that certificate on your backend server. Azure Applicaiton Gateway V2 Certification Issue, https://docs.microsoft.com/en-us/azure/application-gateway/certificates-for-backend-authentication#export-trusted-root-certificate-for-v2-sku, https://docs.microsoft.com/en-us/azure/application-gateway/ssl-overview#end-to-end-tls-with-the-v2-sku, Enabling end to end TLS on Azure Application Gateway, articles/application-gateway/ssl-overview.md, https://docs.microsoft.com/en-us/azure/cloud-shell/overview. End-to-end SSL with Application Gateway v2 requires the backend server's certificate to be verified in order to deem the server Healthy. Or, if Pick host name from backend address is mentioned in the HTTP settings, where the backend address pool contains a valid FQDN, this setting will be applied. 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). Configure that certificate on your backend server. I did not find this error message listed here https://learn.microsoft.com/en-us/azure/application-gateway/application-gateway-backend-health-troubleshooting. Find centralized, trusted content and collaborate around the technologies you use most. This article describes the symptoms, cause, and resolution for each of the errors shown. PS : Dont forget to upload the CER file to the HTTP settings in ApplicationGateway before you do the Health Check. So, I created a default site pointed it to wwwroot, and selected one of my already installed certificates (you can probably PowerShell an SSL for this tbh, but I chose to re-use an already existing one) you dont have to supply a hostname, just a dummy site with an authenticated cert on port 443. If your certificate is working on browser directly hitting the app and not with AppGW then what is the exact problem? The issue was on certificate. Verify that the FQDN entered in the backend pool is correct and that it's a public domain, then try to resolve it from your local machine. We have not faced any issues with HTTP sites but we are facing issues with end-to-end SSL. Please log in using one of these methods to post your comment: You are commenting using your WordPress.com account. For a TLS/SSL certificate to be trusted, that certificate of the backend server must be issued by a CA that's included in the trusted store of Application Gateway. I will clean-up some of my older comments to keep it generic to all since the issue has been identified. Export trusted root certificate (for v2 SKU): 566), Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. For more information about how to extract and upload Trusted Root Certificates in Application Gateway, see Export trusted root certificate (for v2 SKU). If you want Application Gateway to probe on a different protocol, host name, or path and to recognize a different status code as Healthy, configure a custom probe and associate it with the HTTP settings. Our current setup includes app gateway v1 SKU integrated with app services having custom domain enabled. This can create problems when uploaded the text from this certificate to Azure. Can you please add reference to relevant Microsoft Docs page you are following? In this article I am going to talk about one most common issue backend certificate not whitelisted, If you check the backend health of the application gateway you will see the error like this The root certificate of the server certificate used by the backend does not match the trusted root certificate added to the application gateway. Save the custom probe settings and check whether the backend health shows as Healthy now. The -servername switch is used in shared hosting environments. Application Gateway must be restarted after any modification to the backend server DNS entries to begin to use the new IP addresses. If there's a custom probe associated with the HTTP settings, SNI will be set from the host name mentioned in the custom probe configuration. In Azure docs, it is clearly documented that you dont have to import Auth certificate in HTTP settings of the backend if your backend application has Global trusted certificate. c. Check whether any NSG is configured. To verify that Application Gateway is healthy and running, go to the Resource Health option in the portal, and verify that the state is Healthy. Posted in Azure Tagged 502webserver, Azure, azure502, azureapplicationgateway, azurecertificate, azurewaf, backend certificate not whitelisted Post navigation Azure Cyber Security: Protect & Secure Your Cloud Infrastructure @TravisCragg-MSFT : Thank you! Next hop: Azure Firewall private IP address. You must be a registered user to add a comment. For new setup, we have noticed that app gateway back-end becomes unhealthy. If the output doesn't show the complete chain of the certificate being returned, export the certificate again with the complete chain, including the root certificate. 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 ? Trusted root certificate mismatch Either allow "HTTP 401" in a probe status code match or probe to a path where the serverdoesn't require authentication. An Azure service that provides a platform-managed, scalable, and highly available application delivery controller as a service. However when I replace all the 3 certificates to my CA cert, it goes red and warm me "Backend server certificate is not whitelisted with Application Gateway" The reason why I try to use CA . Message: Status code of the backend's HTTP response did not match the probe setting. During SSL negotiation , Client sends "Client Hello" and Server Responds with "Server Hello" with its Certificate to the Client. If your certificate is working on browser directly hitting the app and not with AppGW then what is the exact problem? OpenSSL> s_client -connect 10.0.0.4:443 -servername www.example.com -showcerts By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. The backend certificate can be the same as the TLS/SSL certificate or different for added security. I have tried to upload root CA instead of using well-known CA and the issue persist. @sajithvasu My apologies for this taking a long time, but there are some strange issues here(as you have already discovered). Ive recently faced with the dreaded 502 Web Server error when dealing with the App Gateway, my Backend Health was screaming unhealthy Backend server certificate is not whitelisted with Application Gateway. Cause: Application Gateway checks whether the host name specified in the backend HTTP settings matches that of the CN presented by the backend servers TLS/SSL certificate. c. If the next hop is virtual network gateway, there might be a default route advertised over ExpressRoute or VPN. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, Azure Application Gateway health probe error with "Backend server certificate is not whitelisted with Application Gateway", When AI meets IP: Can artists sue AI imitators? Message: Application Gateway could not connect to the backend. https://docs.microsoft.com/en-us/azure/application-gateway/application-gateway-end-to-end-ssl-powershell, Azure Cyber Security: Protect & Secure Your Cloud Infrastructure, Send Text & WhatsApp Messages for Azure VM Status with Azure Automation, Migrate SOAR Use Cases from Splunk to Microsoft Sentinel, Azure Defender and Azure Sentinel Alerts Bi-Directional Sync. Application Gateway WAF end to end SSL - Microsoft Community Hub In that case, I suggest you to create an Azure Support ticket to take a closer look at internal diagnostics of your app gateway instance considering it's still occurring after troubleshooting. Also, in this example, you'll use the Windows Certificate Manager tool to export the required certificates. Ended up swapping to App Gateway V2 instead using the Trusted CA cert option on the backend http settings. Below is what happens during SSL negotiation when you have single chain cert and root in the AppGW. This will take some time to track down, fix, and the docs will need to be updated with limitations & best practices. Thanks. Check the network security group (NSG) settings of the backend server's network adapter and subnet and whether inbound connections to the configured port are allowed. If the backend server response for the probe request contains the string unauthorized, it will be marked as Healthy. If probes are routed through a virtual appliance and modified, the backend resource will display a 200 status code and the Application Gateway health status can display as Unknown. Backend pools show as unhealthy in azure application gateway For the server certificate to be trusted we need the Root certificate in Trusted Root Cert Store , usually if you are having certs issued by Godaddy,Digicert,Vergion like Third party Vendors you dont have to do anything because they are automatically trusted by your client/browser. By clicking Sign up for GitHub, you agree to our terms of service and I will wait for your response. After the server starts responding Azure Application Gateway with an internal APIM Otherwise, it will be marked as Unhealthy with this message. For the v1 SKU, authentication certificates are required, but for the v2 SKU trusted root certificates are required to allow the certificates. For File name, name the certificate file. Sub-service: <---> Open the Application Gateway HTTP Settings page in the Azure portal. The error says that Root cert is not whitelisted on the AppGW , but you might have a valid Third party certificate on the backend , and more over if you try to access the backend directly bypassing the Application Gateway you will not see any issues related to certificate in the browser. This is the exact thing what we do when import .CER file in the HTTP Settings of the Application Gateway. And each pool has 2 servers . 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. certificate. when the backend server cert hits AppGW after Server Hello , AppGW tries to check who issued the certificate and it finds that it was issued by Intermediate certificate but then it does not have information about Intermediate cert, like who issued the cert and what is the root certificate of that intermediate certificate. -> Same certificate with private key from applicaton server. Sure I would be glad to get involved if needed. Learn more about Application Gateway diagnostics and logging. Ensure that you add the correct root certificate to whitelist the backend. craigclouditpro your a lifesaver thanks for posting this friend ! document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Design a site like this with WordPress.com, Troubleshoot backend health issues in Azure Application Gateway | Microsoft Docs. @EmreMARTiN , you mentioned your backend certificate is from "Digicert" which is already a well-known trusted CA. For more information about how to extract and upload Trusted Root Certificates in Application Gateway, see Export trusted root certificate (for v2 SKU). d. To check the effective routes and rules for a network adapter, you can use the following PowerShell commands: If you don't find any issues with NSG or UDR, check your backend server for application-related issues that are preventing clients from establishing a TCP session on the ports configured. OpenSSL s_client -connect 10.0.0.4:443 -servername www.example.com -showcerts. ID: <---> Cause: When you create a custom probe, you can mark a backend server as Healthy by matching a string from the response body. Azure Nwtworking> Azure Application Gateway: 502 error due to backend certificate not whitelisted in the AppGW, https://techcommunity.microsoft.com/t5/azure-networking-blog/azure-application-gateway-502-error-due-to-backend-certificate/ba-p/3271805, If you are using Azure Application Gateway as Layer 7 WAF for End to End SSL connectivity , you might have come across Certificate related issues most of the times. Azure Application Gateway: 502 error due to backend certificate not If you don't mind can you please post the summary of the root here to help people who might face similar issue. It is required for docs.microsoft.com GitHub issue linking. The certificate that has been uploaded to Application Gateway HTTP settings must match the root certificate of the backend server certificate. or from external over WAF ? 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/ Issue within certification chain using azure application gateway Move to the Certification Path view to view the certification authority. Now, this is the frustrating partwithin IIS, all of my sites are bound too each specified certificate (sharing a single cert across all the sites wont work for this scenario because of the difference in SSL and URL names), What the MSFT document (https://docs.microsoft.com/en-us/azure/application-gateway/application-gateway-end-to-end-ssl-powershell) fails to tell you, is that you need a Default SITE binding to a certificate, without SNI ticked. The authentication certificate is the public key of backend server certificates in Base-64 encoded X.509 (.CER) format. with your vendor and update the server settings with the new You signed in with another tab or window. User without create permission can create a custom object from Managed package using Custom Rest API, the Allied commanders were appalled to learn that 300 glider troops had drowned at sea. The certificate added to Backend HTTP Setting to authenticate the backend servers can be the same as the certificate added to the listener for TLS termination at application gateway or different for enhanced security. Which was the first Sci-Fi story to predict obnoxious "robo calls"? @EmreMARTiN , following up to see if the support case resolved your issue. ", The UDR on the Application Gateway subnet is set to the default route (0.0.0.0/0) and the next hop is not specified as "Internet.". Service unavailable. Or, you can use Azure PowerShell, CLI, or REST API. An authentication certificate is required to allow backend instances in Application Gateway v1 SKU. Failing endpoint is missing root CA as working one has it. On the App Gateway side, there are 6 public listeners are on the App Gateway with public .pfx certs, and 6 authentication certificates (.cer) within the HTTPsSettings, a single backendpool with both VMs configured, and various rules created. The status retrieved by any of these methods can be any one of the following states: If the backend health status for a server is healthy, it means that Application Gateway will forward the requests to that server. Below is what happens during SSL negotiation when you have single chain cert and root in the AppGW. To automate the approach above, within my template I extracted the .cer and .pfx into base64 string using the below PowerShell command: This gave me the ability to upload this into Key Vault, and reference the Secret within my template parameter file, so no credentials or keys are stored in templates, theyre all in Key Vault (all kinds of secure). In this example, we'll use a TLS/SSL certificate for the backend certificate, export its public key and then export the root certificate of the trusted CA from the public key in base64 encoded format to get the trusted root certificate. f. Select Save and verify that you can view the backend as Healthy. After you've figured out the time taken for the application to respond, select the. The application gateway then tries to connect to the server on the TCP port mentioned in the HTTP settings. Hope this helps. A few things to check: a. Note that this .CER file must match the certificate (PFX) deployed at the backend application. 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. If you have an ExpressRoute/VPN connection to the virtual network over BGP, and if you're advertising a default route, you must make sure that the packet is routed back to the internet destination without modifying it. Making sure your App Gateway has the authenticated cert installed on the HTTPs backend settings, with the appropriate Rules & Probe setup and bobs your uncle, I got full Health back, and all my sites were live and kicking. here is the sample command you need to run, from the machine that can connect to the backend server/application. Which ability is most related to insanity: Wisdom, Charisma, Constitution, or Intelligence? Next hop: Internet. Opinions, tips, and news orbiting Microsoft. To do that, follow these steps: Message: The validity of the backend certificate could not be verified. To check the health of your backend pool, you can use the Now Clients will check the Server certificate and confirm if the certificate is issued by Trusted root or not. This is the exact thing what we do when import .CER file in the HTTP Settings of the Application Gateway. Backend Health page on the Azure portal. Certificates signed by well known CA authorities whose CN matches the host name in the HTTP backend settings do not require any additional step for end to end TLS to work. Users can also create custom probes to mention the host name, the path to be probed, and the status codes to be accepted as Healthy. Cause: After Application Gateway sends an HTTP(S) probe request to the To learn more visit https://aka.ms/authcertificatemismatch" I have some questions in regards to application gateway and need help with the same : To Answer we need to understand what happens in any SSL/TLS negotiation. Configuration details on Applicaiton Gateway: i am stuck with that issue, i am thinking maybe it can be a bug but can not be sure. You should do this only if the backend has cert which is issued by internal CA, I hope we are clear till now on why we import Authenticate cert in the HTTP settings of the AppGW and when we use the option "Use Well Known CA", But the actual problem arises if you are using a Third party Cert or Internal CA Cert which has Intermediate CA and then Leaf certificate, Most of the orgs for security reasons use Root Cert----> Intermediate Cert ------> Leaf Cert , even Microsoft follows the same for bing , you can check yourself as below, Now lets discuss what exactly is the confusion here if we have multiple Chain Cert, Check this below when you have single chain certificate , then there will be no confusion with appgw , if your root CA is Global trusted just select "Use Trusted Root CA" option in HTTPsettings, If you root CA is Internal CA , then import that Top root cert in .cer format and upload it in the HTTP settings.