
This is version 2.2 of an YP (NIS version 2) Server for Linux, but it
also runs under other OS like SunOS 4.1.x, Solaris 2.x, AIX, HP-UX,
IRIS, Ultrix and OSF1 (alpha).

This is NOT an NIS+ (NIS version 3) Server !

See the file COPYING for copying restrictions. It is available under
the GNU General Public License. 

The primary ftp site for ypserv is:
ftp://ftp.kernel.org/pub/linux/utils/net/NIS

ypserv does not longer have support for tcp_wrappers. You need to
use /var/yp/securenets to allow/deny queries from other hosts.

This version has support for the ndbm database from Sun.  gdbm is
about 3 times faster for most YP functions, except yp_first/yp_next.
gdbm has a runtime from O(n) for viewing all entries with this, ndbm
has a runtime from O(n*n) !  Very bad for big maps and initgroups,
initgroups will need about 22 minutes for a group file with 10.000
entries and ndbm, with gdbm, only 20 seconds. The load of the server
is the same, but gdbm needs much more memory for caching.

WARNING: NEVER use libdb1/libdb2 in ndbm compat mode, this does NOT work!

1024 Byte limit in NIS protocoll:
---------------------------------
The NIS protocoll has one important limit: keys and data are limited
to 1024 bytes. ypserv 1.3.8 and glibc 2.1 could handle keys and data,
which is bigger 1024 bytes. This will not work with older ypserv or
Linux libc versions like libc5 or glibc 2.0! If you use it with such
systems, it will break NIS support! I don't know, if commercial Unix
versions support it.


For more NIS or NIS+ related stuff, look at
http://www.suse.de/~kukuk/nis/ or http://www.suse.de/~kukuk/nisplus/

Thorsten Kukuk <kukuk@suse.de>, 29. October 2001
