We have purchased an SSL certificate and need to provide the CSR. From reading earlier postings, I believe I have the correct command for doing that. However, I am confused as to what to use for the Common Name. It says “server FQDN or YOUR name”. I don’t know what they mean by YOUR name (if someone cares to explain, i’ll be happy to read it), so I’ll focus on the FQDN.

I am running Ubuntu 14.04. For this question, I will use mydomain.com as our domain name.

When I run hostname, I get “mydomain” as the response. the /etc/hostname file looks like: localhost mydomain mydomain.com www.mydomain.com

When I enter ‘hostname -f’, I get 'localhost’. Should I set my FQDN to mydomain.com or mydomain.mydomain.com (or something else)?


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2 answers

if you dns is setup correctly a host lookup for your domain name should come back with

# host domain.com
domain.com has address of

IP address is just representative of your IP. If the dns is set up properly then put in your FQDN for the common name.

I got no idea what is the ‘earlier posting’ you read.
But if your ssl certificate is for aaa.domain.com, then you will have to input aaa.domain.com.

  • No, you cannot use a cert for aaa.domain.com with bbb.domain.com.
  • Yes, a single cert can represent multiple DN. (subjectAltName)
  • Yes, there is a 'wild-card’ cert, which can fit *.domain.com.