Local DNS on windows - when "nslookup" works but "ping" fails

After upgrading my router I somehow managed to break DNS name resolution on local network, but, obviously, only for Windows machines. After some trial and error, I managed to find relevant DHCP settings on my WRT3200ACM: IP reservation also allows to edit host name for that IP.

So, first part is done, DNS works:

> nslookup ngst-osx
Server:  Linksys01640
Address:  192.168.1.1

Name:    ngst-osx
Address:  192.168.1.138

But next part is disappointing:

> ping ngst-osx
Ping request could not find host ngst-osx. Please check the name and try again

How can this be? nslookup can definitely resolve the IP, so DNS works. After some googling around seems like the trick is to suffix it with a dot to make Windows host name resolution use DNS as the method.

> ping ngst-osx.

Pinging ngst-osx [192.168.1.138] with 32 bytes of data:
Reply from 192.168.1.138: bytes=32 time=117ms TTL=64
Reply from 192.168.1.138: bytes=32 time=341ms TTL=64