ypserv(1M)
ypserv, ypbind - NIS server and binder processes
As shipped in IRIX 6.5.19. Unchanged since IRIX 6.5.
NAME ypserv, ypbind - NIS server and binder processes SYNOPSIS /usr/etc/ypserv [ -iv ] [ -t timeout ] [ -L logflags ] /usr/etc/ypbind [ -s ] [ -v ] [ -ypset | -ypsetme ] [ server ] DESCRIPTION The network information service (NIS) provides a simple network lookup service consisting of databases and processes. The databases are dbm(3B) files in a directory tree rooted at /var/yp. These files are described in ypfiles(4). The processes are /usr/etc/ypserv, the NIS database lookup server, and /usr/etc/ypbind, the NIS binder. The programmatic interface to NIS is described in ypclnt(3N). Administrative tools are described in yppush(1M) ypxfr(1M) yppoll(1M) ypwhich(1), and ypset(1M). Tools to see the contents of NIS maps are described in ypcat(1), and ypmatch(1). Database generation and maintenance tools are described in ypinit(1M), ypmake(1M), and makedbm(1M). Both ypbind and ypserv are daemon processes typically activated at system startup time from /etc/init.d/network if the configuration flags ``yp'' and ``ypserv'' are set on (see network(1M)). The yp configuration state must be on for ypserv to be on. ypserv runs only on NIS server machines with a complete NIS database. ypbind runs on all machines using NIS, that is, both servers and clients. The ypserv daemon's primary function is to look up information in its local database of NIS maps. The operations performed by ypserv are defined for the implementor by the NIS protocol specification, and for the programmer by the header file <rpcsvc/yp_prot.h>. Communication to and from ypserv is by means of RPC calls. Lookup functions are described in ypclnt(3N), and are supplied as C-callable functions in /usr/lib/libsun.a. There are four lookup functions, all of which are performed on a specified map within some NIS domain: Match, Get_first, Get_next, and Get_all. The Match operation takes a key, and returns the associated value. The Get_first operation returns the first key-value pair from the map, and Get_next can be used to enumerate the remainder. Get_all ships the entire map to the requester as the response to a single RPC request. 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(1M), however, they will be visible.) Other functions are used within the NIS subsystem itself, and are not of general interest to NIS clients. They include Do_you_serve_this_domain?, Transfer_map, and Reinitialize_internal_state. The function of ypbind is to remember information that lets client processes on a single node communicate with some ypserv process. ypbind must run on every machine which has NIS client processes; ypserv may or may not be running on the same node, but must be running somewhere on the network or subnet. The information ypbind remembers is called a binding - the association of a domain name with the internet address of the NIS 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 comes in, 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 node or a remote node may be queried for the binding of a particular domain by using the ypwhich(1) command. Bindings are verified before they are given out to a client process. If ypbind is unable to speak to 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 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 NIS server (typically one that is less-heavily loaded) available on the net. If ypbind is invoked with the hostname or IP address of an NIS server for the domain, the domain will be permanently bound to that server. With this option, ypbind will not verify that the specified server is running, hence it will never unbind the domain and never broadcast for a new server. (ypset(1M) can be used to change to a different server in case the original does fail.) ypbind also accepts requests to set its binding for a particular domain if enabled with the -ypset or -ypsetme options. The request is usually generated by the NIS subsystem itself. ypset(1M) is a command to access the Set_domain facility. It is for unsnarling messes. Note that the Set Domain procedure only accepts requests from processes running as root. YPSERV OPTIONS The following options can be specified in /etc/config/ypserv.options: -f forklimit limits the number of processes ypserv can fork at any given time. (The default is 20.) -i allows ypserv to resolve non-local host name and address lookups with the 4.3BSD Internet Domain Name System (DNS) server, named(1M). Positive and negative answers from the DNS server are cached - see the -t option to change the cache timeout. Send SIGHUP to ypserv to flush its DNS query cache. This is useful when a named database is updated and ypserv has a stale answer. -L logflags specifies the type(s) of information to be logged in /var/yp/ypserv.log (see below), in addition to error messages. logflags is a comma-separated list of one or more of: dispatch (show request type and requester IP address), interdomain (show queries to DNS server), and querycache (show results from DNS query cache). -v ``Verbose'' - display messages to stderr instead of the logfile. -t timeout sets the DNS query cache timeout interval to the specified value in seconds. The default is 600 seconds. YPBIND OPTIONS The following options can be specified in /etc/config/ypbind.options: -s Secure. When specified, only ypservers bound to a reserved port are used. This allows for a slight increase in security in completely controlled environ- ments, where there are no computers operated by untrusted individuals. It offers no real increase in security. -v Verbose. When specified, ypbind will log a message using syslog(3B) when it broadcasts domain requests, when it binds a domain after broadcasts, and when it executes successful Set_domain requests. -ypset ypset(1M) may be used to change the binding. This option is very dangerous, and only should be used for debugging the network from a remote machine. -ypsetme ypset(1M) may be issued from this machine, security is based on IP address checking, which can be defeated on network where untrusted individuals may inject packets. This option does not provide that much security. server The IP address or hostname of a permanent NIS server for the default domain. This option is useful when there is no NIS server on the local network. Note that although it is possible to set up a local network without any local NIS servers, this practice is not recommended. FILES If the file /var/yp/ypserv.log exists when ypserv starts up, log information will be written to this file. /etc/config/ypserv.options /etc/config/ypbind.options SEE ALSO named(1M), network(1M), ypcat(1), ypmatch(1), yppush(1M), ypwhich(1), ypxfr(1M), ypset(1M), ypclnt(3N), ypfiles(4), NIS protocol specification