The following describes how the nfsmapid daemon uses the /etc/nsswitch.conf and /etc/resolv.conf files:
nfsmapid uses standard C library functions to request password and group information from back-end name services. These name services are controlled by the settings in the /etc/nsswitch.conf file. Any changes to the nsswitch.conf file affect nfsmapid operations. For more information about the nsswitch.conf file, see the nsswitch.conf(4) man page.
To ensure that the NFS version 4 clients are capable of mounting file systems from different domains, nfsmapid relies on the configuration of the DNS TXT resource record (RR), _nfsv4idmapdomain. For more information about configuring the _nfsv4idmapdomain resource record, see nfsmapid and DNS TXT Records. Also, note the following:
The DNS TXT RR should be explicitly configured on the DNS server with the desired domain information.
The /etc/resolv.conf file should be configured with the desired parameters to enable the resolver to find the DNS server and search the TXT records for client and server NFS version 4 domains.
For more information, see the following: