ndb/query and ndb/ipquery look directly in the ndb files.
ndb/query does simple direct queries based on
the given attribute and value, ndb/ipquery
searches more extensively up through the subnet
hierarchy.  they are both good tools
to check basic functioning of an ndb file.  if they don't
produce sensible results, it's unlikely cs will.
ndb/query and (probably) ndb/ipquery do not talk to
ndb/cs or ndb/dns at all.

ndb/csquery simply opens /net/cs and speaks its protocol,
which expects strings of the form
	net!host!service
and replies with translations of them:

	term% ndb/csquery
	> net!plan9.bell-labs.com!9fs
	/net/il/clone 204.178.31.2!17008!fasttimeout
	/net/tcp/clone 204.178.31.2!564
	/net/il/clone 204.178.31.2!17008
cs relies on dns to translate domain names to ip addresses.
it does not expect a plain name such as `p9'.  it translates
dial(2) addresses.

there's a special case that's also useful in checking whether
your host, subnet and net defaults for services are reasonable.
	net!$attr!service
looks for the given attribute `attr' through the subnet
hierarchy starting at the host and working up.  thus
the dial(2) string `net!$fs!9fs' dials the (default) file server
configured for the current node, and the translation can
be checked by:
	term% ndb/csquery
	> net!$fs!9fs
	/net/il/clone 144.32.112.69!17008!fasttimeout
	/net/tcp/clone 144.32.112.69!564
	/net/il/clone 144.32.112.69!17008
i don't know without a lot of grepping
how much the $attr is used now but it is used
to find an authentication server in the absence of an authdom
(see /sys/src/libauthsrv/authdial.c).  it doesn't really matter
because the point here is that $xyz can be used to check that
cs gives a sensible value for xyz for the current node.

ndb/dnsquery opens /net/dns and uses its protocol:
	ndb/dnsquery
	> bell-labs.com ns
	bell-labs.com ns	ns.research.att.com
	bell-labs.com ns	yeats.pa.bell-labs.com
	bell-labs.com ns	crufty.research.bell-labs.com
	bell-labs.com ns	ns1.research.bell-labs.com
	bell-labs.com ns	dirty.research.bell-labs.com
	bell-labs.com ns	ns2.research.bell-labs.com
	> plan9.bell-labs.com
	plan9.bell-labs.com ip	204.178.31.2