How do I make DNS resolve names that are not fully qualified?

I have foo.com setup.
I have a machine called macfile
I have an A record for macfile.foo.com
and an alias for macfile -> macfile.foo.com

I have also tried simply an A record for macfile.

In both cases the name macfile does not resolve correctly. I have to add the FQDN suffix foo.com which kind of takes the fun out of having my own DNS.

What is the correct way to do this? Am I missing the point of what an alias is for?

Thanks any DNS Gurus out there. It’s doing m head in.