System Administration Commands ypbind(1M)
NAME
ypbind - 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). Administra-
tive 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 ser-
vice. 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 infor-
mation that lets all NIS client processes on a node communi-
cate with some NIS server process. ypbind must run on every
machine which has NIS client processes. The NIS server may
or may not be running on the same node, but must be running
somewhere on the network. If the NIS server is a NIS+ server
in NIS (YP) compatibility mode, see the NOTES section of the
ypfiles(4)man page for more information.
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, either a ypserv process serving the
domain or an rpc.nisd process in "YP-compatibility mode"
serving NIS+ directory with name the same as (case sensi-
tive) 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. All the hosts in the NIS servers
file must be listed in either the /etc/hosts or
/etc/inet/ipnodes files along with their IP addresses. 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 pro-
cess 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 analogous
to ypbind with no options in earlier
Sun releases and is recommended 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 com-
mand. 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
/etc/inet/hosts
/etc/inet/ipnodes
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWnisu |
|_____________________________|_____________________________|
SEE ALSO
svcs(1), ypcat(1), ypmatch(1), ypwhich(1), ifconfig(1M),
rpc.nisd(1M), svcadm(1M), ypinit(1M), ypset(1M),
ypclnt(3NSL), hosts(4), ipnodes(4), ypfiles(4), attri-
butes(5), smf(5)
NOTES
ypbind 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.
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