Tip: enter privileged mode with enable, then configure terminal.
Type show access-lists any time to review your work, or ? for a command list.
Northwind Pottery Studio runs its small storefront network behind a single edge router, Edge1. Since the weekend, three Internet hosts have been pelting the studio's public interface (GigabitEthernet0/0) with junk traffic and scan attempts. The upstream provider is investigating, but you need relief now.
Stand up a temporary standard access list, number 12, that drops traffic from the three offending sources while still letting every other host reach the studio. Apply it inbound on the edge interface. This is a stopgap, so you do not need to save the configuration.