Personal firewall for large business

Come somebody advise me if there is a solution available that can meet
our requirements.

We need a firewall like McAfee or the Microsoft firewall that will
allow us to restrict all ports except a few when employees use their
PC's at home. We also want to be able to have a second setting so when
the same laptop is within the network ports can be opened up as the
security is much higher. The firewall maybe switched off internally if
a solutions like this does not exist.

Another requirement is that we can manage the firewall easily for
example be able to use Ms group policy or McAfee e-policy to manage
rules.

As you may be able to tell I'm not a huge techie and the requirements
are not set in stone but any suggestions would be appreciated even is
its just things that I should consider, the client is a big corporate
so it has to be as secure as possible and as easy to manage as possible.

Riyaz.G@gmail.com