If the certificate wasn't issued by a trusted CA (for example, if a self-signed certificate was used), users should upload the issuer's certificate to Application Gateway. 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. Microsoft Alias: <--->. A few things to check: a. . By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Configure that certificate on your backend server. You should see the root certificate details. For example, run the following command: Test-NetConnection -ComputerName www.bing.com -Port 443. The probe requests for Application Gateway use the HTTP GET method. Also check whether any NSG/UDR/Firewall is blocking access to the Ip and port of this backend. Ensure that you create a default website in the IIS with-in the VM without the SNI enabled and you should not see this error. I am 3 backend pools . Asking for help, clarification, or responding to other answers. For File name, name the certificate file. Now you may ask why it works when you browse the backend directly through browser. The authentication certificate is the public key of backend server certificates in Base-64 encoded X.509(.CER) format. If your certificate is working on browser directly hitting the app and not with AppGW then what is the exact problem? Most of the browsers are thick clients , so it may work in the new browsers but reverse proxies like Application Gateway wont behave like our browsers they only trust the certificates if the backend sends the complete chain. I will wait for the outcome. If you're using Azure default DNS, check with your domain name registrar about whether proper A record or CNAME record mapping has been completed. Only HTTP status codes of 200 through 399 are considered healthy. 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. This is the exact thing what we do when import .CER file in the HTTP Settings of the Application Gateway. Select the root certificate and then select View Certificate. Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey, Azure Application Gateway Probe Configuration, Azure App Gateway gives Error 404 but backend probe is healthy, Azure Application Gateway Health Probe Error, Azure Application Gateway : Backend server certificate expired. @JeromeVigne did you find a solution in your setup? or is that all the backend pools has to serve the request for one application ? @TravisCragg-MSFT: Thanks for checking this. Check the backend server's health and whether the services are running. Allow the backend on the Application Gateway by uploading the root certificate of the server certificate used by the backend. 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. PS : Dont forget to upload the CER file to the HTTP settings in ApplicationGateway before you do the Health Check. Your email address will not be published. If you receive this error message, the CN of the backend certificate doesn't match the host name configured in the custom probe, or the HTTP settings if Pick hostname from backend HTTP settings is selected. You can use any tool to access the backend server, including a browser using developer tools. @sajithvasu This lab takes quite a long time to set up! 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. "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. @EmreMARTiN , following up to see if the support case resolved your issue. The default route is advertised by an ExpressRoute/VPN connection to a virtual network over BGP. AppGW is a PaaS instance , by default you wont get access to the Applicaiton Gateway. This is the exact thing what we do when import .CER file in the HTTP Settings of the Application Gateway. Message: Time taken by the backend to respond to application gateway's health probe is more than the timeout threshold in the probe setting. Currently we are seeing issues with app gateway backend going unhealthy due to backend auth cert. 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. If it is, check the DNS server about why it can't resolve to the IP address of the specified FQDN. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Do not edit this section. 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Otherwise please share the message in that scenario without adding root explicitly. @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. Select the root certificate and then select, In the Certificate properties, select the, Verify the CN of the certificate from the details and enter the same in the host name field of the custom probe or in the HTTP settings (if. The issue was on certificate. This will take some time to track down, fix, and the docs will need to be updated with limitations & best practices. The application gateway then tries to connect to the server on the TCP port mentioned in the HTTP settings. After CA autohority re-created the certificate problem was gone. Now you may ask why it works when you browse the backend directly through browser. Check whether the backend server requires authentication. Applicaiton works fine on the backend servers with 443 certificate from Digicert. Which language's style guidelines should be used when writing code that is supposed to be called from another language? The other one which certificate is still valid and does not need renewal is green. If the backend server doesn't 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. Internal server error. Choose the destination manually as any internet-routable IP address like 1.1.1.1. (LogOut/ If they don't match, change the probe configuration so that it has the correct string value to accept. To troubleshoot this issue, check the Details column on the Backend Health tab. For details on this Openssl command you can refer toTroubleshoot backend health issues in Azure Application Gateway | Microsoft Docs , Look for the sub topic Trusted root certificate mismatch. If you see an Unhealthy or Degraded state, contact support. In 5e D&D and Grim Hollow, how does the Specter transformation affect a human PC in regards to the 'undead' characteristics and spells? (LogOut/ I will clean-up some of my older comments to keep it generic to all since the issue has been identified. to your account. To learn how to create NSG rules, see the documentation page. b. 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. Or, if Pick hostname from backend HTTP settings is selected in the custom probe, SNI will be set from the host name mentioned in the HTTP settings. https://learn.microsoft.com/en-us/azure/application-gateway/ssl-overview#end-to-end-tls-with-the-v2-sku. Verify that the response body in the Application Gateway custom probe configuration matches what's configured. to your account. To ensure the application gateway can send traffic directly to the Internet, configure the following user defined route: Address prefix: 0.0.0.0/0 But if the backend health for all the servers in a backend pool is unhealthy or unknown, you might encounter problems when you try to access -Verify return code: 19 (self signed certificate in certificate chain). -verify error:num=19:self signed certificate in certificate chain craigclouditpro your a lifesaver thanks for posting this friend ! Here is a blog post to fix the issue. Follow steps 1-10 in the preceding section to upload the correct trusted root certificate to Application Gateway. Message: The Common Name (CN) of the backend certificate doesn't match the host header of the probe. Check whetheraccess to the path is allowed on the backend server. 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. On the Export File Format page, select Base-64 encoded X.509 (.CER)., and then click Next. AppGW is a PaaS instance , by default you wont get access to the Applicaiton Gateway. 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. Change the host name or path parameter to an accessible value. Make sure https probe is configured correctly as well. Check whether the server is listening on the port that's configured. To resolve the issue, follow these steps. For example: Cause: Every certificate comes with a validity range, and the HTTPS connection won't be secure unless the server's TLS/SSL certificate is valid. An authentication certificate is required to allow backend instances in Application Gateway v1 SKU. To find out the reason, check OpenSSL diagnostics for the message associated with error code {errorCode}. Message: Body of the backend's HTTP response did not match the error. On the Details tab, select the Copy to File option and save the file in the Base-64 encoded X.509 (.CER) format. The following steps help you export the .cer file in Base-64 encoded X.509(.CER) format for your certificate: If you can't find the certificate under Current User\Personal\Certificates, you may have accidentally opened "Certificates - Local Computer", rather than "Certificates - Current User"). 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.