Investigation and solution

Since my own account is a NIS account, I cannot use that on the clients.

[Warning]Warning

I try to use the root account, but the ssh times out on the NIS first, before even trying the root account. This is a security problem.

The servers don't accept remote root login, so I seem to have no access to the institute. However, the students' domain still has machines that will accept my username (which is an indication that DHCP might not be the problem), and via them I can get to the NIS server. From there, I can get to the clients, and NIS is indeed the problem. (I cannot su to my account.) However, the NIS settings on the client are correct, and restarting the NIS client doesn't solve the problem.

Restarting the NIS server does solve the problem. But it reduces my possibilities for finding out what the problem was in the first place.