NNAAMMEE
iirrss..ccoonnff -- Information Retrieval System configuration file
SSYYNNOOPPSSIISS
iirrss..ccoonnff
DDEESSCCRRIIPPTTIIOONN
The irs(3) functions are a set of routines in the C library which provide
access to various system maps. The maps that irs currently controls are
the following: passwd, group, services, protocols, hosts, networks and
netgroup. When a program first calls a function that accesses one of
these maps, the irs configuration file is read, and the source of each
map is determined for the life of the process.
If this file does not exist, the irs routines default to using local
sources for all information, with the exception of the host and networks
maps, which use the Domain Name System (DNS).
Each record in the file consists of one line. A record consists of a
map-name, an access-method and possibly a (comma delimited) set of
options, separated by tabs or spaces. Blank lines, and text between a #
and a newline are ignored.
Available maps:
Map name Information in map
========= ==================================
passwd User authentication information
group User group membership information
services Network services directory
protocols Network protocols directory
hosts Network hosts directory
networks Network "network names" directory
netgroup Network "host groups" directory
Available access methods:
Access method Description
============= =================================================
local Use a local file, usually in /etc
dns Use the domain name service (includes hesiod)
nis Use the Sun-compatible Network Information Service
irp Use the IRP daemon on the localhost.
Available options:
Option Description
======== ================================================
continue don't stop searching if you can't find something
merge don't stop searching if you CAN find something
The continue option creates ``union namespaces'' whereby subsequent
access methods of the same map type can be tried if a name cannot be
found using earlier access methods. This can be quite confusing in the
case of host names, since the name to address and address to name map-
pings can be visibly asymmetric even though the data used by any given
access method is entirely consistent. This behavior is, therefore, not
the default.
The merge option only affects lookups in the groups map. If set, subse-
quent access methods will be tried in order to cause local users to
appear in NIS (or other remote) groups in addition to the local groups.
EEXXAAMMPPLLEE
# Get password entries from local file, or failing that, NIS
passwd local continue
passwd nis
# Build group membership from both local file, and NIS.
group local continue,merge
group nis
# Services comes from just the local file.
services local
protocols local
# Hosts comes first from DNS, failing that, the local file
hosts dns continue
hosts local
# Networks comes first from the local file, and failing
# that the, irp daemon
networks local continue
networks irp
netgroup local
NNOOTTEESS
If a local user needs to be in the local host's ``wheel'' group but not
in every host's ``wheel'' group, put them in the local host's _/_e_t_c_/_g_r_o_u_p
``wheel'' entry and set up the ``groups'' portion of your _/_e_t_c_/_i_r_s_._c_o_n_f
file as:
group local continue,merge
group nis
NIS takes a long time to time out. Especially for hosts if you use the
--dd option to your server's ``ypserv'' daemon.
It is important that the _i_r_s_._c_o_n_f file contain an entry for each map. If
a map is not mentioned in the _i_r_s_._c_o_n_f file, all queries to that map will
fail.
The classic NIS mechanism for specifying union namespaces is to add an
entry to a local map file whose name is ``+''. In IRS, this is done via
``continue'' and/or ``merge'' map options. While this results in a small
incompatibility when local map files are imported from non-IRS systems to
IRS systems, there are compensating advantages in security and configura-
bility.
FFIILLEESS
/etc/irs.conf The file iirrss..ccoonnff resides in _/_e_t_c.
