Where I work we still have many solaris machines and our logins are managed via NIS. Is there a hashing function that is supported for logins on solaris, linux and BSD that we can use other than the DES based one?
For NIS, you'd need to ensure that every machine that touches passwords via NIS is configured to use the same algorithm when users change passwords. On Solaris, just configure CRYPT_* in /etc/security/policy.conf the same on every machine. (See the policy.conf man page — in short, you want to change the default algorithm to 1 [or whatever] and set __unix__ to be deprecated.) On Linux and *BSD, how you do it depends on the distro/version.
Fun fact about changing passwords in NIS: When a yppasswd client contacts rpc.yppasswdd to change a user's password, the user's new password is sent crypt()ed, but the user's old password is sent in the clear.