Import a my own little ypxfrd protocol. Note that this protocol is
_NOT_ the same as Sun's, which is proprietary.
This basically impliments an RPC-based file transfer protocol which
lets a slave server suck over a raw map database file from the master.
This is many times faster than the normal method, which requires reading
the records from ypserv via yp_all() and then creating a new database
on the fly, particularly when you have many tens of thousands of
records in a map (e.g. a huge passwd database).
The protocol number I chose falls within the 'user-specified' range.
Maybe we should register it with Sun so we can get an official vendor
number for it. :)
