I am considering a caching/forwarding nameserver to be used by internal servers to speed up name resolving.
Is there a way to calculate some reference values to figure out its requirements? I simply took the average size of a zone file and made a projection up to an estimated number of zones to get an average size in mb. But I am not sure if I can take that result as a reference.
How would you do this?
Clarification / More info: Currently, there are 3 SMTP Servers and 1 Webapp which do DNS-Lookups, two of the SMTP relays are used for mass-mailing. They will most likely get between one and three more smtp relays.
The specs I am targetting at is mainly RAM.