IPS arguments

[Hugo Vinicius Garcia Razera <hviniciusg () gmail com>]

Hello Gentleman's,

I have finished a penetration testing to a client like a month ago.
The company i worked for used some practices that i don't agree with.
that's one of the reasons i resigned. any way they managed to shell
the audited company a CISCO IPS using the results of the pen test.

Well the thing is that the CIO of that company is refusing to install
the IPS on their network even after his company has already put a buy
order for the equipment and said IPS is know on their building but he
refuses to install such equipment, augmenting that it is totally
unnecessary because they all ready have an Microsoft ISA server
Firewall in place, and symantec enpoint protection on the clients
machine.

Can any one point me why, they need an IPS?

The old company i worked for wants me to penetrate their network, to
proof them they need an IPS . this time I'm thinking on deploying an
old Trojan i coded.

but i would like to have more compelling arguments on why some one needs an IPS

thanks for the time replying to my questions

Hugo