There are two conventional approaches to creating these DNS entries. For example, ph.hivnet.fr could not contain a MX record. An alternative approach would be to create an A record for each of the IP addresses associated with ph.hivnet.fr, e.g. ph.hivnet.fr. Each site has it's own set of requirements that may make one approach better than the other. This is only likely to be appropriate if the mirror servers are exact copies of the original server.
Some services require that a client have more information than the server's domain name.
For example, an LDAP client needs to know a starting search base within the Directory Information Tree in order to have a meaningful dialogue with the server. This document does not attempt to address this problem. It would appear to be in everyone's interest to narrow the choice of alias down to a single name. Sites with existing CCSO servers using some of these aliases may find it desirable to use all three. This increases the likelihood of the service being found.