E-Lab 11.2.1e - Standard ACL
Configure a standard access list for the local router Sofia.
Create an entry that permits access only to the internal 12.0.0.0 network.
Sofia wants to permit access from the outside world to inside network 12.0.0.0, but not 13.0.0.0. 
A CCNA student suggests placing an ACL on Serial 0.
Step 1
Activate privileged EXEC mode.
Step 2
Enter global configuration mode.
Step 3
Create a standard access-list 1 that permits traffic from the local class A network address 12.0.0.0.
Due to the implicit deny at the end of the access-list, network 13.0.0.0 will not be able to exit the Sofia router.
Step 4
Now enter interface configuration mode for serial 0 to apply the access-list.
Step 5
Apply access-list 1 to the serial interface such that filtering occurs on inbound traffic.
Step 6
Type end to exit the configuration session.
Step 7
Type show access-lists to view the access-list that was created.
Step 8
View the ip interface information for Serial 0 to verify that the list is being applied.
Explain where else the CCNA student might have placed the access-list.