Question: dns naming conventions?

OK, question to the dns-hosting-it-specialists.

Say you have a host, e.g. haddock.moulinsart.tld, with ip address a.b.c.d.

There is an A record haddock.moulinsart.tld pointing to that ip, and a reverse pointer record which points back to haddock.moulinsart.tld.
You might of course have several other A’s and CNAME’s and more pointing to a.b.c.d.

This host also has extra ip addresses on (virtual adapters on) the same NIC, e.g. a.b.c.e, a.b.c.f, a.b.c.g.


    1. When this host acts as mail exchange, would you point the MX records to haddock.moulinsart.tld or to another, maybe more relevant, A record?
    2. How would you ‘name’ those extra ip’s (as in which A records would be the primary name for that IP, and which A record would be the target of the pointer records for that ip?)
    3. How would any of this be different if there is more than 1 physical network card, and hence more than 1 ip which could be called ‘primary’? (Note that I’m talking about a full hosting server, not just a router, for which there probably are other specific naming conventions.)

There obviously is no mandatory rule for this (AFAIK) and no RFC is very strict on this. I’m just curious what you guys think is the best and cleanest naming scheme.