Standard ACLs only examine the source IPv4 address. The destination of the packet and the ports involved are not considered.

The decision process for a standard ACL is mapped in the figure. Cisco IOS software tests addresses against the conditions in the ACL one by one. The first match determines whether the software accepts or rejects the address. Because the software stops testing conditions after the first match, the order of the conditions is critical. If no conditions match, the address is rejected.