Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Mail Systems
Eclipse Documentation

How To Guides
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Problem Solutions
Privacy Policy




Linux NIS / NIS+ Tutorial
Previous Page Home Next Page

11.3. Length of Map entries

The length of one entry is limited by the NIS protocol to 1024 characters. You can't just increase this value and recompile the system. Every system that uses NIS v2 expects key and data values to be no more than 1024 bytes in size; if you suddenly make YPMAXRECORD larger on your client and server, you will break interoperability with all other systems on your network that use NIS. To make it work right, you'd have to go to every vendor that supports NIS and get them to all make the change at the same time. Chances are you won't be able to do this.

With glibc 2.1 and newer this limit was removed from the glibc NIS implementation. So it is possible under Linux to use longer entries, but only if you have no other NIS clients or servers in your network.

To allow the creation of NIS maps with a longer entry, you need to add the --no-limit-check option to the makedbm call in /var/yp/Makefile.

The result should look like:

DBLOAD = $(YPBINDIR)/makedbm -c -m `$(YPBINDIR)/yphelper --hostname` --no-limit-check

WARNING: This breaks the NIS protocol and even if Linux supports it, not all Applictions running under Linux works with this change!

There is another way of solving this problem for /etc/group entries. This idea is from Ken Cameron:

1. Break the entry into more than one line and name each group
   slightly differnet.

2. keep the GID the same for all.

3. have the first entry with the right group name and the GID.
   I don't put any user names in this one.

What happens is that going by user name you pick up the GID when the code
reads it. Then going the other way it stops after the first match of GID
and takes that name. It's ugly but works!
Linux NIS / NIS+ Tutorial
Previous Page Home Next Page

  Published under the terms of the Open Publication License Design by Interspire