If the two machines have fixed addresses there's no reason to use
dns at all.

You should have a /lib/ndb/local that lists the network with the
appropriate auth server and fs server.  For example:

ipnet=robsnet ip=199.199.9.0
	ipgw=199.199.9.1
	fs=199.199.9.2
	auth=199.199.9.3

Or you can use symbolic names instead of the ip addresses:

ipnet=robsnet ip=199.199.9.0
	ipgw=199.199.9.1
	fs=robsfs.rob.net
	auth=robsauth.rob.net

ip=199.99.9.2 dom=robsfs.rob.net
ip=199.99.9.3 dom=robsauth.rob.net

and if you want them to boot off of a plan9 dhcp/bootp/tftp server

ipnet=robsnet ip=199.199.9.0
	ipgw=199.199.9.1
	fs=robsfs.rob.net
	auth=robsauth.rob.net

ip=199.99.9.2 dom=robsfs.rob.net
	ether=123456789012
	bootf=/386/9pcfs
ip=199.99.9.3 dom=robsauth.rob.net
	ether=123456789013
	bootf=/386/9pccpu