Switch it off and on again
Customer: "Hi Pete you know how I keep having to reboot my router to get a good service well it's getting a bit silly now"
Me: "Erm you didn't need to reboot your router, you had some machines infected on your network that was banging every port under the sun!"
Customer: "Well when I reboot the router it's fine for about half an hour?"
Me: "Yes because you severed the link to the Internet when you rebooted the router, once the connection was re-established the spyware or whatever it is started banging the ports again!"
Customer: "Oh erm?"
Me: "Even a blind man could see that?"
Customer: "What shall I do?"
Me: "I'll give you the machines IP take it off the network, clean it get some anti spyware and bollock the user"
Customer: "Can you do that then?"
Thank god it's Friday