idmapd(8) — Linux manual page


RPC.IDMAPD(8)            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

       is the NFSv4 ID <-> name mapping daemon.  It provides
       functionality to the NFSv4 kernel client and server, to which it
       communicates via upcalls, by translating user and group IDs to
       names, and vice versa.

       The system derives the user part of the string by performing a
       password or group lookup.  The lookup mechanism is configured in

       By default, the domain 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 system'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

       Note that on more recent kernels only the NFSv4 server uses .
       The NFSv4 client instead uses nfsidmap(8), and only falls back to
       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 times).

       -f           Runs in the foreground and prints all output to the

       -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

       -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.


       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 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 software has been developed by Marius Aamodt Eriksen

COLOPHON         top

       This page is part of the nfs-utils (NFS utilities) project.
       Information 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
       ⟨git://⟩ on
       2023-12-22.  (At that time, the date of the most recent commit
       that was found in the repository was 2023-12-05.)  If you
       discover any rendering problems in this HTML version 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

GNU                         February 3, 2003               RPC.IDMAPD(8)

Pages that refer to this page: nfs(5)nfs.conf(5)nfsconf(8)nfsdclnts(8)