RPC.IDMAPD(8)            BSD System Manager's Manual           RPC.IDMAPD(8)

NAME         top

     rpc.idmapd — NFSv4 ID <-> Name Mapper

SYNOPSIS         top

     rpc.idmapd [-h] [-f] [-v] [-C] [-S] [-p path] [-c path]

DESCRIPTION         top

     rpc.idmapd is the NFSv4 ID <-> name mapping daemon.  It provides func‐
     tionality to the NFSv4 kernel client and server, to which it communi‐
     cates via upcalls, by translating user and group IDs to names, and vice

     The system derives the part of the string by performing a password or
     group lookup.  The lookup mechanism is configured in /etc/idmapd.conf

     By default, the part of the string is the system's DNS domain name.  It
     can also be specified in /etc/idmapd.conf if the system is multi-homed,
     or if the system's DNS domain name does not match the name of the sys‐
     tem's Kerberos realm.

     When the domain is not specified in /etc/idmapd.conf the local DNS
     server will be queried for the _nfsv4idmapdomain text record. If the
     record exists that will be used as the domain. When the record does not
     exist, the domain part of the DNS domain will used.

     Note that on more recent kernels only the NFSv4 server uses rpc.idmapd.
     The NFSv4 client instead uses nfsidmap(8), and only falls back to
     rpc.idmapd if there was a problem running the nfsidmap(8) program.

     The options are as follows:

     -h           Display usage message.

     -v           Increases the verbosity level (can be specified multiple

     -f           Runs rpc.idmapd in the foreground and prints all output to
                  the terminal.

     -p path      Specifies the location of the RPC pipefs to be path.  The
                  default value is "/var/lib/nfs/rpc_pipefs".

     -c path      Use configuration file path.  This option is deprecated.

     -C           Client-only: perform no idmapping for any NFS server, even
                  if one is detected.

     -S           Server-only: perform no idmapping for any NFS client, even
                  if one is detected.


     rpc.idmapd recognizes the following value from the [general] section of
     the /etc/nfs.conf configuration file:

                  Equivalent to -p.

     All other settings related to id mapping are found in the
     /etc/idmapd.conf configuration file.

EXAMPLES         top

     rpc.idmapd -f -vvv

     Runs rpc.idmapd printing all messages to console, and with a verbosity
     level of 3.

FILES         top

     /etc/idmapd.conf, /etc/nfs.conf

SEE ALSO         top

     idmapd.conf(5), nfs.conf(5), nfsidmap(8)

AUTHORS         top

     The rpc.idmapd software has been developed by Marius Aamodt Eriksen

COLOPHON         top

     This page is part of the nfs-utils (NFS utilities) project.  Informa‐
     tion about the project can be found at  If you have a bug
     report for this manual page, see  This page was obtained
     from the project's upstream Git repository;a=summary on
     2017-05-03.  If you discover any rendering problems in this HTML ver‐
     sion of the page, or you believe there is a better or more up-to-date
     source for the page, or you have corrections or improvements to the
     information in this COLOPHON (which is not part of the original manual
     page), send a mail to

BSD                           February 3, 2003                           BSD

Pages that refer to this page: nfs(5)nfs.conf(5)