Where is the linux client name set?

It's been a couple of years since I've needed to configure a linux client (my Solaris systems are still running their old BB clients). And I'm confused with what I'm seeing. This is on a _very_ minimal server installation with client; compiled from source.

I have files in ~/client/tmp/ of the form msg.xymonx.state.ak.us.txt (so fully-qualified host.domain name). Yet the first line of that file is:
   client xymonx.linux linux

So the message body being sent to the xymon server contains the short host name. But the client is writing the file onto the disk with the fully-qualified name.

The xymon server reports my client messages as 'ghosts', and correctly picks them up if I put a client alias in hosts.cfg
   client:xymonx
I'd like to do away with that alias.

Where is my linux client picking up this short name?

-- 
    Do things because you should, not just because you can.

John Thurston    XXX-XXX-XXXX
user-ce4d79d99bab@xymon.invalid
Department of Administration
State of Alaska