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I have created Windows Server VM in Azure and deployed my site to IIS, which is now accessible at https://mysite.westeurope.cloudapp.azure.com/

however I get certificate error when I try to visit it from outside the vm.

how do I configure the VM to have proper https without certificate errors (just like app service - mysite.azurewebsites.net)?

Liero
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  • Have you looked at https://blogs.msdn.microsoft.com/azuresecurity/2015/07/13/certificate-management-in-azure-dos-and-donts/ ? TL;DR... you can't. – micker Aug 02 '19 at 14:31
  • the blog is not relevant I think. it is relates to azure services like website, not vm. It states: "They already have HTTPS enabled through the default Microsoft multi-domain cert". Well, obviously VM doesn't. – Liero Aug 02 '19 at 18:13
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    You deployed your site to IIS so... you have a website. You cannot get a certificate for a subdomain of a Microsoft owned domain. If you want proper HTTPS, you'll have to obtain a domain name of your own and then a certificate which is bound to that domain. You can either purchase that certificate through Azure or an external provider and upload it to your Key Vault. – micker Aug 02 '19 at 19:26

3 Answers3

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As the comments from micker @micker, you can't get an SSL certificate for this subdomain westeurope.cloudapp.azure.com which is owned by Microsoft.

Since you host your websites on Azure VM, you could purchase a domain then get an SSL certificate for your own domain, then bind the SSL certificate to your custom domain in IIS on the Azure VM. You can either purchase that certificate through Azure or an external provider or get a free SSL cert from Let's Encrypt.

However, if you just want to have a test in your test environment, you can use a self-signed certification with this DNS name like vma.centralus.cloudapp.azure.com. You can follow steps in How To Create A SHA-256 Self-Signed Certificate on the Azure VM then export this cert .cer format file on the Azure VM and import the .cer cert under the mmc---certificate---local machine---Trusted root certification Authorities on the machine where you want to access the websites. Please note this It's not recommended to use self-signed cert in your production environment.

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Nancy
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    It's worthy to note here that simply creating a subdomain within your private domain to have it forward visitors to the Azure VM address also won't work. It's necessary to a) create a completely new domain name as stated above by Nancy, b) manage the new domain's DNS settings and create an "A" record there to point to the Azure VM's IP address (you better have set a static/permanent IP address for it beforehand!), and then link the new Standard SSL certificate's domain preference to that new domain name. You should then be able to download and use the certificate in your VM's app where needed. – ShieldOfSalvation May 01 '20 at 22:46
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I had same issue, and I found resolution without custom domain using following additional azure settings.

  1. create Azure WAF, add custom rules to deny if not in IP list - this is if you need ip whitelisting, useful if your main domain uses akamai or other edge routing to point to external hosting of subdomains, you can use whitelist to restrict access to the akamai or other servers, though this takes some big lists you must paste of ranges one row at a time. Set any other web app firewall rules you want enforced for allow/deny.
  2. Create Azure Front Door named like you want as an endpoint url e.g. myappfrontdoor will make myappfrontdoor.azurefd.net. in backend pool specify the your public-ip shared dns name (see step 3) like myapptest..cloudapp.azure.com.
  3. This is the important step : in Settings at top of front door designer, disable cert validation. in routing rules config, no condition, forward to backend pool setup in prior step. This ignores the fact that you cannot cert your cloudapp.azure.com endpoint, and wraps it with a *.azurefd.net certificate.
  4. In your azure firewall, Edit NAT rules, set rule name myapp-web-fd-... , tcp, ip address, 147.243.0.0/16 (this is Azure's front door backend ip range). destination should be the firewall's own public ip. destination port 443, translated address should be the target vm's azure internal ip, target port - service port.

Now you will have a site like myappfrontdoor.azurefd.net.

Note that Azure Front Door and WAF have their own pricing costs, so maybe it is cheaper for you to buy a domain. Hopefully you are also using Azure Firewall, though expensive. If not, one could point to public ip directly on NSG or on vm itself but I wouldn't skip having a firewall for a public server. There is a standing Azure enhancement request to get Azure Front Door to recognize certificates, but it was triaged 2 years ago and still not added, so not sure if it will be worked. If it ever does get worked, devs could make own cert auth and self-signed cert with expirations to more securely hook front door to azure internal vm. For now, have to rely on the front door backend setting, waf, and azure firewall to have these things routed.

There are some options in Akamai and other edge routing systems to import cert and self-created authority sort of, but I've not tried that yet, so cannot confirm this would cleanly wrap your azure site without cert errors. You can make a self-signed authority using openssl commands as noted in other posts out and about on the web.

Lanthar Dalton
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The simplest and cheapest option is to purchase a domain and use a cname dns record to map your new domain to your Azure subdomain address - an "A" record is not required. Also per answer above, a WAF is expensive and possibly unnecessary for a test set up (but a requirement for a production website). You can use Certbot and NGINX to create a free Lets Encrypt certificate for your domain and assign it to your website.

Adding a Public IP Address, Load Balancer, and Network Security Group to your Azure Resource Group may also be required to provide access to your website. This is largely how my test configuration is set up except I'm using a Linux VM, have a single wildcard certificate, and use NGINX to reverse proxy 3 websites.

David Clarke
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