How to add an entry in a subdomain without adding the domain

So you need a subdomain in your dns but you only need one and don’t want to create a whole new file… well it’s really easy…

 

Assume that you are editing the zone file for b.domain.com and you want to add www.a.b.domain.com just add this to b.domain.com

 

www.a.b.domain.com    IN A 10.10.10.41