Solaris 下刷新(清空)DNS缓存
使用命令:nscd -i hosts
有关nscd守护进程的说明参照下面的说明。
NAME
nscd - name service cache daemon
SYNOPSIS
/usr/sbin/nscd [-f configuration-file] [-g] [-e cachename, yes
| no] [-i cachename]
DESCRIPTION
The nscd daemon is a process that provides a cache for most
name service requests. The default configuration-file
/etc/nscd.conf determines the behavior of the cache daemon.
See nscd.conf(4).
nscd provides caching for the passwd(4), group(4), hosts(4),
ipnodes(4), exec_attr(4), prof_attr(4), user_attr(4), eth-
ers(4), rpc(4), protocols(4), networks(4), bootparams(4),
audit_user(4), auth_attr(4), services(4), netmasks(4),
printers(4), project(4) databases through standard libc
interfaces, such as gethostbyname(3NSL),
getipnodebyname(3SOCKET), gethostbyaddr(3NSL), and others.
Each cache has a separate time-to-live for its data; modify-
ing the local database (/etc/hosts, /etc/resolv.conf, and so
forth) causes that cache to become invalidated upon the next
call to nscd. The shadow file is specifically not cached.
getspnam(3C) calls remain uncached as a result.
nscd also acts as its own administration tool. If an
instance of nscd is already running, commands are passed to
the running version transparently.
When running with per-user lookups enabled (see
nscd.conf(4)), nscd forks one and only one child process
(that is, a per-user nscd) on behalf of the user making the
request. The per-user nscd will use the credentials of the
user to open a per-user connection to the name repository
configured for the per-user style of lookups. The lookup
will be performed in the child process. The results are
cached in the process and are available only to the same
user. The caches are managed exactly the same as the main
nscd daemon manages its own caches. Subsequent requests from
the user will be handled by that per-user nscd until it ter-
minates. The per-user nscd uses a configurable inactivity
time-to-live (TTL) value and terminates itself after the
inactivity TTL expires.
The maximum number of per-user nscds that can be created by
the main nscd is configurable (see nscd.conf(4)). After the
maximum number of them are created, the main nscd will use
an LRU algorithm to terminate less active child nscds as
needed.
The main nscd daemon creates, monitors, and manages all the
child nscds. It creates a user's own nscd upon receiving the
user's first per-user lookup. When the nscd daemon is
started, if per-user lookups are enabled, it checks to
ensure all conditions are met before getting ready to create
a per-user nscd. When the daemon is stopped, it terminates
all the per-user nscds under its control.
Per-user nscds use the same configuration as the main nscd.
They read and use the same default configuration file or the
one specified with the -f command line option. Once the con-
figuration is read, the per-user nscd will use it for its
entire lifetime.
OPTIONS
Several of the options described below require a cachename
specification. Supported values for cachename are: passwd,
group, hosts, ipnodes, exec_attr, prof_attr, user_attr, eth-
ers, rpc, protocols, networks, bootparams, audit_user,
auth_attr, services, netmasks, printers, and project.
-f configuration-file
Causes nscd to read its configuration data from the
specified file.
-g
Prints current configuration and statistics to standard
output. This is the only option executable by non-root
users.
-e cachename, yes|no
Enables or disables the specified cache.
-i cachename
Invalidate the specified cache.
EXAMPLES
Example 1 Stopping and restarting the nscd daemon.
example# svcadm disable system/name-service-cache
example# svcadm enable system/name-service-cache
FILES
/etc/nscd.conf Determines athe behavior of the cache daemon.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
SEE ALSO
svcs(1), svcadm(1M), getspnam(3C), gethostbyname(3NSL),
getipnodebyname(3SOCKET), audit_user(4), auth_attr(4), boot-
params(4), ethers(4), exec_attr(4), group(4), hosts(4), net-
masks(4), networks(4), nscd.conf(4), nsswitch.conf(4),
passwd(4), printers(4), prof_attr(4), project(4), proto-
cols(4), rpc(4), services(4), user_attr(4), attributes(5)
NOTES
The output from the -g option to nscd is subject to change.
Do not rely upon it as a programming interface.
The nscd service is managed by the service management facil-
ity, smf(5), under the service identifier:
svc:/system/name-service-cache
Administrative actions on this service, such as enabling,
disabling, or requesting restart, can be performed using
svcadm(1M). The service's status can be queried using the
svcs(1) command.

