idmapd.conf(5)

✨ NAME ✨

okay bestie, this is idmapd.conf(5) — the config file for libnfsidmap. It's giving "NFSv4 name mapping but make it a vibe." No cap.

---

📜 SYNOPSIS 📜

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

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

---

🫶 DESCRIPTION 🫶

The idmapd.conf configuration files 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 — Verbosity level of debugging (Default: 0)
• Domain — 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)
• No-Strip — 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")
• Reformat-Group — Winbind has a quirk whereby doing a group lookup in UPN format (e.g. staff@americas.example.com) 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")
• Local-Realms — A comma-separated list of Kerberos realm names that may be considered equivalent to the local realm name. For example, users juser@ORDER.EDU and juser@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 🎀

• Nobody-User — Local user name to be used when a mapping cannot be completed.
• Nobody-Group — Local group name to be used when a mapping cannot be completed.

🌈 [Translation] section variables 🌈

• Method — 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)
• GSS-Methods — 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@REALM = localusername

💜 [REGEX] section variables 💜

If the "regex" translation method is specified, the following variables within the [REGEX] section are used to map between NFS4 names and local IDs.

• User-Regex — Case-insensitive regular expression that extracts the local user name from an NFSv4 name. Multiple expressions may be concatenated with '|'. The first match will be used. There is no default. A basic regular expression for domain DOMAIN.ORG and realm MY.DOMAIN.ORG would be:

^DOMAIN\([^@]+)@MY.DOMAIN.ORG$

• Group-Regex — Case-insensitive regular expression that extracts the local group name from an NFSv4 name. Multiple expressions may be concatenated with '|'. The first match will be used. There is no default. A basic regular expression for domain DOMAIN.ORG and realm MY.DOMAIN.ORG would be:

^([^@]+)@DOMAIN.ORG@MY.DOMAIN.ORG$|^DOMAIN\([^@]+)@MY.DOMAIN.ORG$

• Prepend-Before-User — Constant string to put before a local user name when building an NFSv4 name. Usually this is the short domain name followed by '´. (Default: none)
• Append-After-User — Constant string to put after a local user name when building an NFSv4 name. Usually this is '@' followed by the default realm. (Default: none)
• Prepend-Before-Group — Constant string to put before a local group name when building an NFSv4 name. Usually not used. (Default: none)
• Append-After-Group — Constant string to put before a local group name when building an NFSv4 name. Usually this is '@' followed by the domain name followed by another '@' and the default realm. (Default: none)
• Group-Name-Prefix — Constant string that is prepended to a local group name when converting it to an NFSv4 name. If an NFSv4 group name has this prefix it is removed when converting it to a local group name. With this group names of a central directory can be shortened for an isolated organizational unit if all groups have a common prefix. (Default: none)
• Group-Name-No-Prefix-Regex — Case-insensitive regular expression to exclude groups from adding and removing the prefix set by Group-Name-Prefix. The regular expression must match both the remote and local group names. Multiple expressions may be concatenated with '|'. (Default: none)

🔥 [UMICH_SCHEMA] section variables 🔥

If the "umich_ldap" translation method is specified, the following variables within the [UMICH_SCHEMA] section are used.

• LDAP_server — LDAP server name or address (Required if using UMICH_LDAP)
• LDAP_base — Absolute LDAP search base. (Required if using UMICH_LDAP)
• LDAP_people_base — Absolute LDAP search base for people accounts. (Default: The LDAP_base value)
• LDAP_group_base — Absolute LDAP search base for group accounts. (Default: The LDAP_base value)
• LDAP_canonicalize_name — Whether or not to perform name canonicalization on the name given as LDAP_server (Default: "true")
• LDAP_follow_referrals — Whether or not to follow ldap referrals. (Default: "true")
• LDAP_use_ssl — Set to "true" to enable SSL communication with the LDAP server. (Default: "false")
• LDAP_ca_cert — Location of a trusted CA certificate used when SSL is enabled (Required if LDAP_use_ssl is true and LDAP_tls_reqcert is not set to never)
• LDAP_tls_reqcert — Controls the LDAP server certificate validation behavior. It can take the same values as ldap.conf(5)'s TLS_REQCERT tunable. (Default: "hard")
• LDAP_timeout_seconds — Number of seconds before timing out an LDAP request (Default: 4)
• LDAP_sasl_mech — SASL mechanism to be used for sasl authentication. Required if SASL auth is to be used (Default: None)
• LDAP_realm — SASL realm to be used for sasl authentication. (Default: None)
• LDAP_sasl_authcid — Authentication identity to be used for sasl authentication. (Default: None)
• LDAP_sasl_authzid — Authorization identity to be used for sasl authentication. (Default: None)
• LDAP_sasl_secprops — Cyrus SASL security properties. It can take the same values as ldap.conf(5)'s sasl_secprops.
• LDAP_sasl_canonicalize — Specifies whether the LDAP server hostname should be canonicalised. If set to yes LDAP lib will do a reverse hostname lookup. If this is not set the LDAP library's default will be used. (Default: None)
• LDAP_sasl_krb5_ccname — Path to kerberos credential cache. If it is not set then the value of environment variable KRB5CCNAME will be used. If the environment variable is not set then the default mechanism of kerberos library will be used.
• NFSv4_person_objectclass — The object class name for people accounts in your local LDAP schema (Default: NFSv4RemotePerson)
• NFSv4_name_attr — Your local schema's attribute name to be used for NFSv4 user names (Default: NFSv4Name)
• NFSv4_uid_attr — Your local schema's attribute name to be used for uidNumber (Default: uidNumber)
• GSS_principal_attr — Your local schema's attribute name for GSSAPI Principal names (Default: GSSAuthName)
• NFSv4_acctname_attr — Your local schema's attribute name to be used for account names (Default: uid)
• NFSv4_group_objectclass — The object class name for group accounts in your local LDAP schema (Default: NFSv4RemoteGroup)
• NFSv4_gid_attr — Your local schema's attribute name to be used for gidNumber (Default: gidNumber)
• NFSv4_group_attr — Your local schema's attribute name to be used for NFSv4 group names (Default: NFSv4Name)
• LDAP_use_memberof_for_groups — 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)
• NFSv4_member_attr — If LDAP_use_memberof_for_groups is true, this is the attribute to be searched for. (Default: memberUid)
• NFSv4_grouplist_filter — An optional search filter for determining group membership. (No Default)

✨ EXAMPLES ✨

okay bestie, here's a whole /etc/idmapd.conf that actually does stuff, so you can just vibe off it 👑

An example /etc/idmapd.conf file:

[General]

Verbosity = 0
Domain = domain.org
Local-Realms = DOMAIN.ORG,MY.DOMAIN.ORG,YOUR.DOMAIN.ORG

[Mapping]

Nobody-User = nfsnobody
Nobody-Group = nfsnobody

[Translation]

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

[Static]

johndoe@OTHER.DOMAIN.ORG = johnny

[Regex]

User-Regex = ^DOMAIN\([^@]+)@DOMAIN.ORG$
Group-Regex = ^([^@]+)@DOMAIN.ORG@DOMAIN.ORG$|^DOMAIN\([^@]+)@DOMAIN.ORG$
Prepend-Before-User = DOMAIN
Append-After-User = @DOMAIN.ORG
Append-After-Group = @domain.org@domain.org
Group-Name-Prefix = sales-
Group-Name-No-Prefix-Regex = -personal-group$

[UMICH_SCHEMA]

LDAP_server = ldap.domain.org
LDAP_base = dc=org,dc=domain

---

📁 FILES 📁

these are the spots where the config actually lives, in the order they get read 💅

• /usr/etc/idmapd.conf
• /usr/etc/idmapd.conf.d/*.conf
• /etc/idmapd.conf
• /etc/idmapd.conf.d/*.conf

Files are read in the order listed. Later settings override earlier settings.

so basically the last one to speak wins, no cap. whatever you drop in later in that list overrides what came before it 🫶

---

👀 SEE ALSO 👀

• idmapd(8)
• svcgssd(8)

go read those too, they're the main characters of this whole saga 🌟

---

🐛 BUGS 🐛

found something cursed? Report bugs to <nfsv4@linux-nfs.org> — they wanna hear it fr fr 🙈

---

and that's a wrap, bestie 🎀 this page is from the 19 Nov 2008 era, filed under idmapd.conf(5) — iconic, timeless, lowkey vintage, and now fully yours 💖✨