how do i prevent users on
my network from running

ypcat passwd

i need help desperately.

try this:

chmod 500 /usr/bin/ypcat

this just makes it accessible only by root.

Also make it immune for modifications, deletion, renaming, linking to by changing attributes,
chattr +i /usr/bin/ypcat

even if one does

chmod 700 ...ypcat

the hacker can get a copy of ypcat , from somewhere , on his floppy and run it on my system . what does one do in that case.

yp sucks. making ypcat exec only by root doesn't solve that problem, not one could a malicious user compile his own ypcat, chances are you are using something like Redhat so all the dolt has to do is grab a RPM...yawn..

there are some things you can do with NIS to make it more secure, however most of the failsafe methods break the purpose and functionality of NIS. For example you can still define local users in the /etc/passwd of all the hosts, however that makes using NIS pointless.

I suggest converting to OpenLDAP. There is redhat documentation regarding this, over at:

http://www.redhat.com/docs/manuals/l...edhattips.html