NFS Services Administrator's Guide

Configuring the Name Service Switch
Chapter 6268
The Name Service Switch determines where your host will look for the
information that is traditionally stored in the following files:
• /etc/mail/aliases
• automounter maps (like /etc/auto_master and /etc/auto_home)
• /etc/group
• /etc/hosts
• /etc/netgroup
• /etc/networks
• /etc/passwd
• /etc/protocols
• /etc/publickey
• /etc/rpc
• /etc/services
You can configure your host to look for each type of information in NIS,
NIS+, or the local /etc file. You can configure your host to consult any
combination of these sources, in any order; however, it is recommended
that you do not configure your host to consult both NIS and NIS+.
For host information (host names and IP addresses), you can configure
your host to consult BIND (DNS) in addition to NIS, NIS+, or the local
/etc/hosts file. Again, it is recommended that you do not configure your
host to consult both NIS and NIS+.
The Name Service Switch on HP-UX 10.30 has a different default
behavior from the Name Service Switch in previous releases. If you are
using the default Name Service Switch configuration (or if you do not
have an /etc/nsswitch.conf file), and you want your host to behave
the same way after you upgrade to HP-UX 10.30, copy the
/etc/nsswitch.hp_defaults file to /etc/nsswitch.conf. See “Default
Configuration” on page 275 for more information.
The ability to consult more than one name service for host information is
often called hostname fallback. The Name Service Switch provides
client-side hostname fallback, because it is used by client-side
programs (for example, gethostbyname) which request host information.