Create clean DNS configurations

Question

I'm concerned about creating a clean / easy managed DNS configuration for a domain.

Every time I have to manage a new domain, previous configurations are just dozens and dozens of A records pointing to IPs. I always use CNAMES as follow:

server1.mydomain.com       A         X.XX.XX.XX
main.mydomain.com       CNAME   server1.mydomain.com
*.mydomain.com             CNAME   main.mydomain.com
...                                    CNAME   main.mydomain.com

This way if I need to switch servers I just change "main" and that's it.

However, I'm concerned about having too many CNAME jumps. Can it have an impact on performance, security, whatever?

Answer 1

Each CNAME level means another request to your DNS server, if I went to test.mydomain.com I'd get a reply saying it was a CNAME for main.mydomain.com, then I'd request main.mydomain.com which is a CNAME for server1.mydomain.com then I'd make a request for server1.mydomain.com which will reply with IP X.XX.XX.XX . So, three requests for 1 IP address.

This means larger replies, and more work for your DNS server. On a small scale this isn't much of an issue, but if you get 100's of thousands of requests for your domain, sending larger replies is not efficient, either in terms of bandwidth or workload on your server, but it is neither illegal, insecure or wrong. If you find it's the best way to manage your domains, weigh the efficiency costs against the increased administrative work you'd have to do and make your choice.