suffix for the Host Name which is'nt needed

[rj.2001]

Hello,

If I do a ping from my pc to the router via

ping wl500gp
I get no answer!

If I do a ping from my pc to the router via

ping wl500gp.router
It works perfectly.

If I do a ping from my router to the router via

ping wl500gp
It works!?!?!

I found out that the suffix comes from the configuration "Domain Name" under IP Config - DHCP Server. If I remove the "Domain Name" I can't send a ping any more to my router!
Is there a way to remove the suffix?

Thanks a lot.