YP server daemon
ypserv is a fundamental part of the
network information system called YP. This server provides information from
YP maps to the YP clients on the network.
A YP map is stored on the server as a Berkeley database. A number
of YP maps are grouped together in a domain.
determines the domains it serves by looking for a directory with the domain
name in /var/yp.
YP hasn't been known for high security through the years. In recent years security has improved by restricting access to the server. In SunOS 4.1 has a new file occurred named /var/yp/securenet. It contains networks the server can assume is secure. For information about the file format, see securenet(5).
Before the author of this server had seen
securenet(5) another format,
ypserv.acl(5), was implemented. This file format makes it possible to
allow and deny hosts and networks access to the server. This file can have
any name since it's given by the argument to
If a host isn't secure, all queries to the server will result in a YP_NODOM result.
If the file /var/yp/ypserv.log exists then messages will be written to the file.
If a directory named the same as the system domainname exists in
/var/yp (i.e., the domainname is “foo”
and the directory /var/yp/foo exists), then
ypserv will be automatically started at boot
On receipt of a hangup signal,
ypserv will reopen the log file and reread its
configuration, including both the map files and the
securenet(5) configuration file.
The options are as follows:
ypservto answer old YP version 1 requests.
- Don't use /var/yp/securenet. Use another file with a different file format. For further information see ypserv.acl(5).
- Use Internet Domain Name System. If a query to map
“hosts.byname” or “hosts.byaddr” fails, make a
DNS query and return the result if successful. Alternately, if these maps
were built on the YP master using
-bthen DNS queries will be done without needing to specify
- Terminate the server after processing aclfile or /var/yp/securenet.
dbopen(3), securenet(5), ypserv.acl(5), Makefile.yp(8), yp(8), ypbind(8)
Mats O Jansson <email@example.com>