Translating IP address on a local network

[Sarah Reichelt]

Hi All,

We have a small network behind a NAT router, with IP addresses either
set manually or by DHCP in the format 192.168.1.xxx.
All the computer's are Macs so they also have Bonjour names e.g.
sarah-mac.local.

I have set up a custom web server based on Andre's RevOnRockets. When
the web server receives a request, the IP address of the requesting
computer is contained in the socket ID. I would like to be able to
translate that to the Bonjour name of the requesting computer as that
would make the logs much more easily read.

Is there a Mac shell command or any way of getting this data for
addresses inside a local network which are not listed on any DNS or
Directory service?

TIA,
Sarah