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STANDARD Printed by: Nora Chuang [nchuang] STANDARD

/build/1111/BRICK/man4/!!!intro.4

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nsswitch.conf(4) nsswitch.conf(4)

If compatibility with the +/- syntax for passwd and group is required, simply modify the entries for

passwd and group to:

passwd: compat

group: compat

If NIS+ is the enterprise level name-service, the default conﬁguration should be modiﬁed to use nisplus

instead of nis for every database on client machines. The ﬁle /etc/nsswitch.nisplus contains a

sample conﬁguration that can be copied to /etc/nsswitch.conf to set this policy.

If the use of +/- syntax is desired in conjunction with nisplus, use the following four entries:

passwd: compat

passwd_compat: nisplus

group: compat

group_compat: nisplus

In order to get information from the Internet Domain Name Service for hosts that are not listed in the

enterprise level name-service, NIS+, use the following conﬁguration and set up the

/etc/resolv.conf ﬁle (see resolver(4) for more details):

hosts: nisplus dns [NOTFOUND=return] ﬁles

Enumeration -- getXXXent()

Many of the databases have enumeration functions: passwd has getpwent() , hosts has gethos-

tent()

, and so on. These were reasonable when the only source was files but often make little sense

for hierarchically structured sources that contain large numbers of entries, much less for multiple sources.

The interfaces are still provided and the implementations strive to provide reasonable results, but the data

returned may be incomplete (enumeration for

hosts is simply not supported by the dns source), incon-

sistent (if multiple sources are used), formatted in an unexpected fashion (for a host with a canonical name

and three aliases, the

nisplus source will return four hostents, and they may not be consecutive), or

very expensive (enumerating a passwd database of 5000 users is probably a bad idea). Furthermore,

multiple threads in the same process using the same reentrant enumeration function (getXXXent_r()

are supported) share the same enumeration position; if they interleave calls, they will enumerate disjoint

subsets of the same database.

In general the use of the enumeration functions is deprecated. In the case of passwd, and group

, it may

sometimes be appropriate to use

fgetgrent() , fgetpwent() , and fgetspent() (see getgrent(3C),

and getpwent(3C), respectively), which use only the

files source.

WARNINGS

Within each process that uses

nsswitch.conf()

, the entire ﬁle is read only once. If the ﬁle is later

changed, the process will continue using the old conﬁguration.

Programs that use the

getXXbyYY() functions cannot be linked statically since the implementation of

these functions requires dynamic linker functionality to access the shared objects

/usr/lib/nss_SSS.sl.1 at run time.

The use of both nis and nisplus as sources for the same database is strongly discouraged since both

the name-services are expected to store similar information and the lookups on the database may yield

different results depending on which name-service is operational at the time of the request.

Misspelled names of sources and databases will be treated as legitimate names of (most likely nonexistent)

sources and databases.

The following functions do not use the switch: fgetgrent() , fgetpwent() , fgetspent(),

getpw(), and putpwent().

Applications linked with libc.1 will display different default actions for NOTFOUND and TRYAGAIN.

Applications linked with libc.1 will have the switch search terminate if the Name Service returns a result of

NOTFOUND or TRYAGAIN.

This will be an issue for exisiting nsswitch.conf ﬁles that specify name service lookup criteria that contains

no <criterion> between <source> entries.

Example: hosts: dns ﬁles

For applications linked with libc.1, the fallback to ﬁles will only occur if

DNS returns UNAVAIL. For all

other applications, the fallback to ﬁles will occur unless

DNS returns SUCCESS.

HP-UX Release 11i: December 2000 − 3 − Section 4−−193

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