I would not expect a standard CS curriculum to have a class on the TCP/IP stack. A networking class, maybe, but more theoretical than on IP implementation details.
If you need somebody that knows the ins and outs of IP, then I suggest your organization look for such things during the hiring process, instead of going through the incredibly expensive process of hiring somebody only to let them go months later.
It sounds like you are a bunch of morons there that have managed to (consistently!) confuse CS and IT.