Peter is a Network Admin.

Explanations:

Unicasts are one-to-one IP transmissions, by disabling this he would disable most network transmissions but still not prevent the smurf attack. Turning of multicast or fragmentation on the router has nothing to do with Peter’s concerns as a smurf attack uses broadcast, not multicast and has nothing to do with fragmentation. Anti-virus protection will not help prevent a smurf attack. A smurf attack is a broadcast from a spoofed source. If directed broadcasts are enabled on the destination all the computers at the destination will respond to the spoofed source, which is really the victim. Disabling directed broadcasts on a router can prevent the attack.