Is there a good rule of thumb to know how much a server can handle in services and usage load?
I have a setup:
I am at a school where there are less than 200 systems and much less than that use the Internet at the same time, web, mail, etc.
for both security and load, what services need to be on separate systems?
Since the firewall is on the NAT, can you do filtering there for porn, etc ( since it is a school ) using iptables, or Squid or.... would that slow the system down too much?
In the DMZ: web, dns, mail, ... can all be on one system, would it be a performance hit. How much can it handle? Is there a good way to know? Would one service make the others more open to attack?
I know it is all kind of broad in topic, but I am looking for general info and a place to start.