idmapd.conf (5) - Linux Manuals

idmapd.conf: configuration file for libnfsidmap


idmapd.conf - configuration file for libnfsidmap


Configuration file for libnfsidmap. Used by idmapd and svcgssd to map NFSv4 name to and from ids.


The idmapd.conf configuration file consists of several sections, initiated by strings of the form [General] and [Mapping]. Each section may contain lines of the form
  variable = value
The recognized sections and their recognized variables are as follows:

[General] section variables

Verbosity level of debugging (Default: 0)
The local NFSv4 domain name. An NFSv4 domain is a namespace with a unique username<->UID and groupname<->GID mapping. (Default: Host's fully-qualified DNS domain name)
In multi-domain environments, some NFS servers will append the identity management domain to the owner and owner_group in lieu of a true NFSv4 domain. This option can facilitate lookups in such environments. If set to a value other than "none", the nsswitch plugin will first pass the name to the password/group lookup function without stripping the domain off. If that mapping fails then the plugin will try again using the old method (comparing the domain in the string to the Domain value, stripping it if it matches, and passing the resulting short name to the lookup function). Valid values are "user", "group", "both", and "none". (Default: "none")
Winbind has a quirk whereby doing a group lookup in UPN format (e.g. staff [at] will cause the group to be displayed prefixed with the full domain in uppercase (e.g. AMERICAS.EXAMPLE.COM\staff) instead of in the familiar netbios name format (e.g. AMERICAS\staff). Setting this option to true causes the name to be reformatted before passing it to the group lookup function in order to work around this. This setting is ignored unless No-Strip is set to either "both" or "group". (Default: "false")
A comma-separated list of Kerberos realm names that may be considered equivalent to the local realm name. For example, users juser [at] ORDER.EDU and juser [at] MAIL.ORDER.EDU may be considered to be the same user in the specified Domain. (Default: the host's default realm name)
Note: If a value is specified here, the default local realm must be included as well.

[Mapping] section variables

Local user name to be used when a mapping cannot be completed.
Local group name to be used when a mapping cannot be completed.

[Translation] section variables

A comma-separated, ordered list of mapping methods (plug-ins) to use when mapping between NFSv4 names and local IDs. Each specified method is tried in order until a mapping is found, or there are no more methods to try. The methods included in the default distribution include "nsswitch", "umich_ldap", and "static". (Default: nsswitch)
An optional comma-separated, ordered list of mapping methods (plug-ins) to use when mapping between GSS Authenticated names and local IDs. (Default: the same list as specified for Method)

[Static] section variables

The "static" translation method uses a static list of GSS-Authenticated names to local user names. Entries in the list are of the form:
 principal [at] REALM = localusername

[UMICH_SCHEMA] section variables

If the "umich_ldap" translation method is specified, the following variables within the [UMICH_SCHEMA] section are used.
LDAP server name or address (Required if using UMICH_LDAP)
Absolute LDAP search base. (Required if using UMICH_LDAP)
Absolute LDAP search base for people accounts. (Default: The LDAP_base value)
Absolute LDAP search base for group accounts. (Default: The LDAP_base value)
Whether or not to perform name canonicalization on the name given as LDAP_server (Default: "true")
Set to "true" to enable SSL communication with the LDAP server. (Default: "false")
Location of a trusted CA certificate used when SSL is enabled (Required if LDAP_use_ssl is true)
The object class name for people accounts in your local LDAP schema (Default: NFSv4RemotePerson)
Your local schema's attribute name to be used for NFSv4 user names (Default: NFSv4Name)
Your local schema's attribute name to be used for uidNumber (Default: uidNumber)
Your local schema's attribute name for GSSAPI Principal names (Default: GSSAuthName)
Your local schema's attribute name to be used for account names (Default: uid)
The object class name for group accounts in your local LDAP schema (Default: NFSv4RemoteGroup)
Your local schema's attribute name to be used for gidNumber (Default: gidNumber)
Your local schema's attribute name to be used for NFSv4 group names (Default: NFSv4Name)
Some LDAP servers do a better job with indexing where searching through all the groups searching for the user in the memberuid list. Others like SunOne directory that search can takes minutes if there are thousands of groups. So setting LDAP_use_memberof_for_groups to true in the configuration file will use the memberof lists of the account and search through only those groups to obtain gids. (Default: false)
If LDAP_use_memberof_for_groups is true, this is the attribute to be searched for. (Default: memberUid)
An optional search filter for determining group membership. (No Default)
Number of seconds before timing out an LDAP request (Default: 4)


An example /etc/idmapd.conf file:

Verbosity = 0
Domain =


Nobody-User = nfsnobody
Nobody-Group = nfsnobody


Method = umich_ldap,nsswitch
GSS-Methods = umich_ldap,static


johndoe [at] OTHER.DOMAIN.ORG = johnny


LDAP_server =
LDAP_base = dc=org,dc=domain


Report bugs to <nfsv4 [at]>


idmapd(8) svcgssd(8)