Network Security

Question 15

How can an ISP secure a customerís computer against port-scans?

It depends on the type of customer.

If the customer doesn't run any services, the ISP can simply block all attempts to access the customer.

If the customer is running services, the ISP could consider the techniques in question 16. If it's know specifically which ports the customer i using, the rest can be firewalled. This'll of course give some administrative problems when the customer wants to add additional services.