Specifications

files directly access ﬁles, for example, to /etc/aliases.

db access via a database.

nis NIS

nisplus

dns Only usable by hosts and networks as an exten-

sion.

compat Only usable by passwd, shadow, and group as an

extension.

Table 2.3: Conﬁguration Options for NSS “Databases”

also it is possible to trigger various reactions with certain lookup re-

sults; details can be found in the man page for nsswitch.conf.

/etc/nscd.conf

The nscd (Name Service Cache Daemon) is conﬁgured in this ﬁle (see

the man pages for nscd and nscd.conf). This affects the data result-

ing from passwd, groups, and hosts. The daemon must be restarted

every time the name resolution (DNS) is changed by modifying the

/etc/resolv.conf ﬁle. The command rcnscd restart serves this

purpose.

Caution

If, for example, caching for passwd is activated, it usually takes

about ﬁfteen seconds until a newly added user is recognized by

the system. By resarting nscd, reduce this waiting period.

Caution

/etc/resolv.conf

As is already the case with the /etc/host.conf ﬁle, this ﬁle, by way

of the resolver library, plays a role in host name resolution.

Speciﬁed are the domain to which the host belongs (keyword search)

and the status of the name server address (keyword name server) to ac-

cess. Multiple domain names can be speciﬁed. When resolving a name

that is not fully qualiﬁed, an attempt is made to generate one by at-

taching the individual search entries. Multiple name servers used by

entering several lines, each beginning with name server. Comments are

preceded by ‘#’ signs.

An example /etc/resolv.conf is shown in File 5.

28 Manual Network Conﬁguration