A stratum 4 client is a system that gets its NTP service from one or more stratum 3 machines and which doesn't provide a service to any other systems. The well-provided-for local network will have some stratum 3 servers, which you should use in preference to any others. However, if there is none then the UIS does provide some stratum 3 servers for general use.
There are three stratum 3 servers in the University you can use in the absence of any local one. These have the DNS aliases:
Setting up a simple stratum 4 client
First, you should ask you local computer support whether there are any stratum 3 NTP servers on your local network. If there are you should use these in preference to the central stratum 3 servers.
If your NTP software can only use a single server, then you should select one of your local stratum 3 servers at random. If you don't have any local servers, select one of ours. (Roll a die if you have problems with picking things randomly.)
If your NTP software can accept a number of servers, then select three of them. Again, give preference to your local servers and use a random selection of our servers to make up the numbers.
If you are running a Unix system that is permanently up on the network, why not set up a stratum 3 server on your network and make it available to your colleagues?