Command
PPP Authentication PAP
Use
This command is used to authenticate a link using PAP.
Syntax
Router(config-if)#ppp authentication pap
Example

In this example, R1’s S1/1 interface is configured to authenticate R3 using PAP.
R1(config)#int s1/1 |
Here we can see that the link now requires authentication.
R3(config)#int s1/1 |
After we provide the configured username and password the link comes up.
R3(config)#int s1/1 |