Hardware and performance

> Our network manager is off and we need to get one ordered soon.

A coup? {-)

> the most users we have had on at one time is 611 though that seems a bit high, id say 250 would be more realistic estimate.

Consult the documentation first: http://docs.moodle.org/en/Installing_Moodle#How_many_users.3F
http://docs.moodle.org/en/Installing_Moodle#Requirements

> Also do i need 2 servers to run one in and one behind the DMZ.

You don't _need_ two. By dividing work, Webserver on one database-server on the other, two can deliver more. Where to put them - Internet, DMZ, LAN - is a matter of (subjectively felt) security and network performance.

> I have had a few user giving me guidence.

Isn't that a bit scary? :-{