ypserv.1m (2010 09)

y
ypserv(1M) ypserv(1M)
normal lookup functions. If you examine the map with
makedbm or yppoll, they are visible (see
makedbm(1M) or yppoll (1M)). Other functions are used within the NIS subsystem and are not of general
interest to NIS clients. These include:
Do_you_serve_this_domain?
Transfer_map
Reinitialize_internal_state
The ypbind daemon remembers information that lets client processes on its machine communicate with
a ypserv process. The ypbind daemon must run on every machine using NIS services, both NIS
servers and clients. The ypserv daemon may or may not be running on a NIS client machine, but it
must be running somewhere on the network or be available through a gateway.
The information that
ypbind remembers is called a binding: the association of a NIS domain name with
the NIS server. This information is cached in the directory
/var/yp/binding/
domain_name in the
file called
cache_binding
. For example, if domain_name is mydomain
, then the information is
cached in
/var/yp/binding/mydomain/cache_binding
.
Client requests drive the binding process. As a request for an unbound domain comes in, the
ypbind
process broadcasts on the network, if the file
/var/yp/binding/
domain_name /ypservers does not
exist, trying to find a
ypserv process serving maps within that NIS domain. If the binding should be
established by broadcasting, at least one
ypserv process must exist on every network. If the file
/var/yp/binding/
domain_name /ypservers is present, then ypbind will try to bind to one of the
NIS servers in the order of its listing in the file. If
ypbind was unable to bind to any one of the servers
available in the list, it will try establishing a binding by broadcasting. The file,
/var/yp/binding/domain_name/ypservers
, containing the list of NIS servers is created by
invoking
ypinit with the -c option (see ypinit(1M)). If ypbind is invoked with a -broadcast
option, ypbind will try to establish a binding by broadcast immaterial of the availability of the file
/var/yp/binding/domain_name/ypservers
; that is, the option -broadcast overrides the
existence of the file
/var/yp/binding/domain_name/ypservers
. Once a binding is established
for a client, it is given to subsequent client requests. Execute
ypwhich to query the ypbind process
(local and remote) for its current binding (see ypwhich (1)).
Bindings are verified before they are given to a client process. If
ypbind is unable to transact with the
ypserv process it is bound to, it marks the domain as unbound, tells the client process that the domain
is unbound, and tries to bind again. Requests received for an unbound domain fail immediately. Gen-
erally, a bound domain is marked as unbound when the node running ypserv crashes or is overloaded.
In such a case, ypbind binds to any NIS server (typically one that is less heavily loaded) that is avail-
able on the network.
The
ypbind daemon also accepts requests to set its binding for a particular domain. ypset accesses the
set_domain facility; it is for unsnarling messes and is not for casual use.
Options
ypserv recognizes the following options:
-l log_file Log diagnostic and error messages to the file, log_file .
If
ypserv is started without the -l option, ypserv writes its messages to
/var/yp/ypserv.log if that file exists.
If
ypbind is started without the -l option, ypbind writes its messages directly to
the system console, /dev/console.
Information logged to the file includes the date and time of the message, the host
name, the process id and name of the function generating the message, and the
message itself. Note that different services can share a single log file since enough
information is included to uniquely identify each message.
-d The NIS service must approach the DNS for more host information. This requires
the existence of a correct /etc/resolv.conf file pointing at a machine running
named. This option enables DNS forwarding regardless of whether or not the
YP_INTERDOMAIN flag is set in the hosts maps. See makedbm(1M). In the
absence of an /etc/resolv.conf file, ypserv complains, but ignores the -d
option.
-v Operate in the verbose mode, printing diagnostic messages to stderr.
2 Hewlett-Packard Company − 2 − HP-UX 11i Version 3: September 2010