NAME

rpcbind — universal addresses to RPC program number mapper (né portmapper)

SYNOPSIS

DESCRIPTION

The rpcbind utility is a server that converts RPC program numbers into universal addresses. It must be running on the host to be able to make RPC calls on a server on that machine.

When an RPC service is started, it tells rpcbind the address at which it is listening, and the RPC program numbers it is prepared to serve. When a client wishes to make an RPC call to a given program number, it first contacts rpcbind on the server machine to determine the address where RPC requests should be sent.

The rpcbind utility should be started before any other RPC service. Normally, standard RPC servers are started by port monitors, so rpcbind must be started before port monitors are invoked.

When rpcbind is started, it checks that certain name-to-address translation-calls function correctly. If they fail, the network configuration databases may be corrupt. Since RPC services cannot function correctly in this situation, rpcbind reports the condition and terminates.

The rpcbind utility can only be started by the super-user.

Access control is provided by /etc/hosts.allow and /etc/hosts.deny, as described in hosts_access(5) with daemon name rpcbind.

OPTIONS

-6

Bind to AF_INET6 (IPv6) addresses only.

-a

When debugging (-d), abort on errors.

-d

Run in debug mode. In this mode, rpcbind will not fork when it starts, will print additional information during operation, and will abort on certain errors if -a is also specified. With this option, the name-to-address translation consistency checks are shown in detail.

-h bindip

IP addresses to bind to when servicing TCP and UDP requests. This option may be specified multiple times and is typically necessary when running on a multi-homed host. If no -h option is specified, rpcbind will bind to INADDR_ANY, which could lead to problems on a multi-homed host due to rpcbind returning a UDP packet from a different IP address than it was sent to. Note that when specifying IP addresses with -h, rpcbind will automatically add 127.0.0.1 and if IPv6 is enabled, ::1 to the list.

-i

“Insecure” mode. Allows calls to SET and UNSET RPC procedures from any host. Normally rpcbind accepts these requests only from the loopback interface for security reasons. This change is necessary for programs that were compiled with earlier versions of the rpc(3) library and do not make those requests using the loopback interface.

-L

Allows old-style local connections over the loopback interface. Without this flag, local connections are only allowed over a local socket, /var/run/rpcbind.sock.

-l

Turns on libwrap connection logging.

-s

Causes rpcbind to change to the user daemon as soon as possible. This causes rpcbind to use non-privileged ports for outgoing connections, preventing non-privileged clients from using rpcbind to connect to services from a privileged port.

-W

Enable libwrap (TCP wrappers) support.

-w

Enable the warmstart feature.

The warmstart feature saves RPC registrations on termination. Any saved RPC registrations are restored on restart if -w is specified. This feature helps avoid RPC service interruption when restarting rpcbind. warmstart support must be compiled in to rpcbind. Portmap (version 2) registrations are stored in /tmp/portmap.file. rpcbind (version 3) registrations are stored in /tmp/rpcbind.file.

NOTES

All RPC servers must be restarted if rpcbind is restarted.

FILES

/var/run/portmap.file

saved portmap registrations file.

/var/run/rpcbind.file

saved rpcbind registrations file.

/var/run/rpcbind.sock

 

/etc/hosts.allow

explicit remote host access list.

/etc/hosts.deny

explicit remote host denial of service list.

SEE ALSO

rpcbind(3), hosts_access(5), hosts_options(5), netconfig(5), rpcinfo(8)

HISTORY

rpcbind is named after version 3 of the protocol, which provides “transport-independent RPC” (TI-RPC). Version 2 of the protocol and the program that implemented it, a predecessor of rpcbind, were called “portmap”, and the program was colloquially known as “portmapper”. The notion of “port” is specific to TCP/IP, so newer, transport-independent versions of the protocol got rid of it, but the old name is still used informally.