A/UX® System Administrator's Reference Sections 1M, 7, and 8

ypserv(lM) ypserv(lM)
Two other functions supply information about the map, rather than
map entries: Get order number, and Get master name.
In fact, both order number-and master name eXist in the -map as
key-value pairs, but the server will not return either through the
normal lookup functions. (If you examine the map with
makedbm(lM), however, they will be visible.)
Other functions are used within the yP subsystem itself, and are
not of general interest to yP clients. They include
Do-you_serve_this_domain?, Transfer_map, and
Reinitialize internal state.
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The function of ypbind is to remember information that allows
client processes on a single node communicate with some ypserv
process. ypbind must run on every machine which has
yP client processes; ypserv mayor may not be running on the
same node, but must be running somewhere on the network.
The information ypbind remembers is called a binding: the association
of a domain name with the internet address of the yP
server, and the port on that host at which the ypserv process is
listening for service requests. The process of binding is driven by
client requests. As a request for an unbound domain is received,
the ypbind process broadcasts on the net. trying to find a ypserv
process that serves maps within that domain. Since the
binding is established by broadcasting, there must be at least one
ypserv process on every net Once a domain is bound by a particular
ypbind, that same binding is given to every client process
on the node. The ypbind process on the local or on a remote
node may be queried for the binding of a particular domain by using
the ypwhich(l) command.
Bindings are verified before they are given out to a client process.
If ypbind is unable to speak to the ypserv process to which it's
bound, it marks the domain as unbound, tells the client process
that the domain is unbound. and tries to bind the domain once
again. Requests received for an unbound domain will fail immediately.
In general, a bound domain is marked as unbound
when the node running ypserv crashes or gets overloaded. In
such a case, ypbind will to bind any yP server (typically one
that is less-heavily loaded) available on the net
ypbind also accepts requests to set its binding for a particular
domain. The request is usually generated by the yP subsystem itself.
ypset(1M) is a command to access the Set_domain fa-
February. 1990
Revision C
2