thats rigth.....to be more specifical this is my config.....

i use a dhcp server...
in the iptables..i have accese permisions using ip vs mac..this to avoid inpersonalitation
th ip tables are on the firewall wich acts as the gateway....
the proxy (squid) is configured to deny any download
the msn passes trougth the proxyand all teh trafic for it..( and other messengers) is monotored a recorded...only the file trasfering....
the files trasfered trougth this services is checked with antivirus software....and if i want i can manually cancell any trasnmition....

the firewalls are totally pakced...they only have ssh opened....
what i'm missing?¿