Whilst not recommended as the primary DHCP server for large networks, Mac OS X Server is quite competent at providing leases for a subnet or two, particularly when coupled with NetBoot services. In our testing lab, we use a Mac OS X server for this exact purpose, serving as a NAT gateway, and providing DHCP and NetBoot services to a subnet, and we have had issues in the past with the underlying bootpd process locking up or too many clients on the subnet exhausting available leases.
With that, I have added a script to check the DHCP service on Mac OS X server. It will work on 10.6-8, and will check that the DHCP service is running, and then return performance data on the number of provided leases and active clients.
Over the next few weeks, I am planning to detail some of the workflows I am using to generate graphs like the one pictured above, giving excellent visibility into the historical performance of your Mac services.