Why can't my mac resolve local hostnames?

[Rilot]

I've never had any issue with this before but tonight I tried to RDP on to my nas box to be greeted with "Unable to resolve hostname NAS".

Can't resolve any local host via ping. I can connect to it in Finder via smb://nas though.
Everything else on my network (4 windows PCs, 2 linux machines) can resolve hostnames.
DNS is assigned via DHCP as being my router, which can also resolve everything by hostname.
Other machines on my LAN can resolve my MacBook

So, the only thing on my LAN that can't resolve local addresses by hostnames is my MacBook. Internet addresses work just fine.

Any ideas?

[edit]
Just been messing around:

andys-pro:~ rilot$ host nas
nas.Osiris has address 192.168.1.249

andys-pro:~ rilot$ nslookup nas
Server: 192.168.1.1
Address: 192.168.1.1#53

Name: nas.Osiris
Address: 192.168.1.249

andys-pro:~ rilot$ ping nas
ping: cannot resolve nas: Unknown host

Huh? Nslookup says it's there and resolving. Host says the same but ping........ nothing.

 

[Deleted member 77746]

I'm sure OSX uses FQDN unless a fully configured DNS is setup and I'm not talking about router DNS.

 

[shine]

You can fix it by following these instructions:

http://apple.stackexchange.com/questions/24018/dns-lookups-fail-with-e-g-ping-but-work-with-host

 

[Rilot]

Nice, thanks.
I don't understand why it was working before but then suddenly stopped resolving.