It is possible to force ypbind to bind to a particular NIS server host for a given domain by using the ypset(8) command. However, ypbind refuses YPBINDPROC_SETDOM requests by default since it has no way of knowing exactly who is sending them. Using the -ypset flag causes ypbind to accept YPBINDPROC_SETDOM requests from any host. This option should only be used for diagnostic purposes and only for limited periods since allowing arbitrary users to reset the binding of an NIS client poses a severe security risk.
-ypsetme
This is similar to the -ypset flag, except that it only permits YPBINDPROC_SETDOM requests to be processed if they originated from the local host.
-s
Cause ypbind to run in secure mode: it will refuse to bind to any NIS server that is not running as root (i.e., that is not using privileged TCP ports).
-S -Xo
.Sm off domainname, server1, server2, server3, ... .Sm on
Allow the system administrator to lock ypbind to a particular domain and group of NIS servers. Up to ten servers can be specified. There must not be any spaces between the commas in the domain/server specification. This option is used to insure that the system binds only to one domain and only to one of the specified servers, which is useful for systems that are both NIS servers and NIS clients: it provides a way to restrict what machines the system can bind to without the need for specifying the -ypset or -ypsetme options, which are often considered to be security holes. The specified servers must have valid entries in the local /etc/hosts file. IP addresses may be specified in place of hostnames. If ypbind cannot make sense out of the arguments, it will ignore the -S flag and continue running normally.
Note that ypbind will consider the domainname specified with the -S flag to be the system default domain.
-m
Cause ypbind to use a ’many-cast’ rather than a broadcast for choosing a server from the restricted mode server list. In many-cast mode, ypbind will transmit directly to the YPPROC_DOMAIN_NONACK procedure of the servers specified in the restricted list and bind to the server that responds the fastest. This mode of operation is useful for NIS clients on remote subnets where no local NIS servers are available. The -m flag can only be used in conjunction with the -S flag above (if used without the -S flag, it has no effect).
