install-comodo-ssl-cert-for-nginx.rst

Setting up a SSL Cert from Comodo

I use Namecheap.com as a registrar, and they resale SSL Certs from a number of other companies, including Comodo.

These are the steps I went through to set up an SSL cert.

Purchase the cert

Prior to purchasing a cert, you need to generate a private key, and a CSR file (Certificate Signing Request). You'll be asked for the content of the CSR file when ordering the certificate.

openssl req -nodes -newkey rsa:2048 -keyout example_com.key -out example_com.csr

This gives you two files:

• example_com.key -- your Private key. You'll need this later to configure ngxin.
• example_com.csr -- Your CSR file.

Now, purchase the certificate¹, wait forever for them to review your purchase. You'll eventually get an email with your PositiveSSL Certificate. It contains a zip file with the following:

• Root CA Certificate - AddTrustExternalCARoot.crt
• Intermediate CA Certificate - PositiveSSLCA2.crt
• Your PositiveSSL Certificate - example_com.crt

Install the Commodo SSL cert

Combine everything for nxinx²:

1. Combine the above crt files into a bundle (the order matters, here):

   cat example_com.crt PositiveSSLCA2.crt AddTrustExternalCARoot.crt >> ssl-bundle.crt

2. Store the bundle wherever nginx expects to find it:

   mkdir -p /etc/nginx/ssl/example_com/
   mv ssl-bundle.crt /etc/nginx/ssl/example_com/

3. Make sure your nginx config points to the right cert file and to the private key you generated earlier:

   server {
       listen 443;
   
       ssl on;
       ssl_certificate /etc/nginx/ssl/example_com/ssl-bundle.crt;
       ssl_certificate_key /etc/nginx/ssl/example_com/example_com.key;
   
       # ...
   
   }

4. Restart nginx.

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1. I purchased mine through the Namecheap.com website.↩

2. Based on these instructions: http://goo.gl/4zJc8↩