ypbind(1M) System Administration Commands ypbind(1M)NAMEypbind - NIS binder process
SYNOPSIS
/usr/lib/netsvc/yp/ypbind [-broadcast | -ypset | -ypsetme]
DESCRIPTION
NIS provides a simple network lookup service consisting of databases
and processes. The databases are stored at the machine that runs an NIS
server process. The programmatic interface to NIS is described in
ypclnt(3NSL). Administrative tools are described in ypinit(1M),
ypwhich(1), and ypset(1M). Tools to see the contents of NIS maps are
described in ypcat(1), and ypmatch(1).
ypbind is a daemon process that is activated at system startup time
from the svc:/network/nis/client:default service. By default, it is
invoked as ypbind-broadcast.ypbind runs on all client machines that
are set up to use NIS. See sysidtool(1M). The function of ypbind is to
remember information that lets all NIS client processes on a node com‐
municate with some NIS server process. ypbind must run on every machine
which has NIS client processes. The NIS server may or may not be run‐
ning 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 a NIS server. The process of binding is driven by
client requests. As a request for an unbound domain comes in, if
started with the -broadcast option, the ypbind process broadcasts on
the net trying to find an NIS server, that is, a ypserv process serving
the domain with a name the same as (case sensitive) the name of the
domain in the client request. Since the binding is established by
broadcasting, there must be at least one NIS server on the net. If
started without the -broadcast option, ypbind process steps through the
list of NIS servers that was created by ypinit -c for the requested
domain. There must be an NIS server process on at least one of the
hosts in the NIS servers file. It is recommended that you list each of
these NIS servers by name and numeric IP address in /etc/hosts. Though
the practice is not recommended, NIS allows you to list servers by
numeric address only, bypassing /etc/hosts. In such a configuration,
ypwhich(1) returns a numeric address instead of a name.
Once a domain is bound by ypbind, that same binding is given to every
client process on the node. The ypbind process on the local node or a
remote node may be queried for the binding of a particular domain by
using the ypwhich(1) command.
If ypbind is unable to speak to the NIS server process it is bound to,
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 wait until the requested domain is
bound. In general, a bound domain is marked as unbound when the node
running the NIS server crashes or gets overloaded. In such a case,
ypbind will try to bind to another NIS server using the process
described above.ypbind also accepts requests to set its binding for a
particular domain. The request is usually generated by the ypset(1M)
command. In order for ypset to work, ypbind must have been invoked with
flags -ypset or -ypsetme.
OPTIONS-broadcast
Send a broadcast datagram using UDP/IP that requests the informa‐
tion needed to bind to a specific NIS server. This option is analo‐
gous to ypbind with no options in earlier Sun releases and is rec‐
ommended for ease of use.
-ypset
Allow users from any remote machine to change the binding by means
of the ypset command. By default, no one can change the binding.
This option is insecure.
-ypsetme
Only allow root on the local machine to change the binding to a
desired server by means of the ypset command. ypbind can verify
the caller is indeed a root user by accepting such requests only on
the loopback transport. By default, no external process can change
the binding.
FILES
/var/yp/binding/ypdomain/ypservers
Lists the servers to which the NIS client is allowed to bind.
/etc/inet/hosts
File in which it is recommended that NIS servers be listed.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │system/network/nis │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOsvcs(1), ypcat(1), ypmatch(1), ypwhich(1), ifconfig(1M), svcadm(1M),
ypinit(1M), ypset(1M), ypclnt(3NSL), hosts(4), ypfiles(4),
attributes(5), smf(5)NOTESypbind supports multiple domains. The ypbind process can maintain
bindings to several domains and their servers, the default domain is
the one specified by the domainname(1M) command at startup time.
The -broadcast option works only on the UDP transport. It is insecure
since it trusts "any" machine on the net that responds to the broadcast
request and poses itself as an NIS server.
The ypbind service is managed by the service management facility,
smf(5), under the service identifier:
svc:/network/nis/client:default
Administrative actions on this service, such as enabling, disabling, or
requesting restart, can be performed using svcadm(1M). The service's
status can be queried using the svcs(1) command.
SunOS 5.11 11 Dec 2009 ypbind(1M)
