Laptops should work away from a network, even if they normally
authenticate/authorize using kerberos/LDAP. Key network-provided user
data (i.e., passwords and NSS) should be cached when a user logs in. I've
done a small amount of work on this. There are still a few major
problems.
See:
http://www.flyn.org/laptopldap/laptopldap.html.
--
Mike