CCNA Complete Guide 2nd Edition.pdf - Cisco Learning Home

- Unidirectional PPP PAP authentication configuration on NAS:
username Client password 0 cisco
!
interface Serial0/0
ip address 10.10.10.2 255.255.255.252
encapsulation ppp
ppp authentication pap [callin]
ppp direction callin
Note: The callin keyword of the ppp authentication pap interface subcommand is optional
- A router configured with the ppp authentication pap interface subcommand will use PAP to
verify the identity of the peer, which means that the peer must present its username and password
to the local device for verification. The local device would use the local username-based
authentication system to verify and authenticate its peer.
- The function of the username {remote-username} password {passwd} statement is
different for PAP and CHAP. With PAP, it is only used to verify that an incoming username and
password; whereas CHAP uses it to generate the response to a challenge and verify a response.
- For one-way PAP authentication, the username {remote-hostname} password {passwd}
statement is only required on the called device to verify the username and password sent by the
calling device; whereas for two-way PAP authentication, it is required on both devices.
- A router configured with the ppp authentication pap callin interface subcommand
configured will only authenticate the peer during incoming calls – it will not authenticate the
peer for outgoing calls.
- The ppp pap sent-username {local-username} password {passwd} interface
subcommand is configured on the calling device to authenticate itself to a remote called device.
The remote device must have the same set of username – password statement configured.
- The ppp direction {callin | callout | dedicated} interface subcommand is introduced in
Cisco IOS Release 12.2T. This command is useful when a router is connected to an interface
type where there is no inherent call direction, eg: a back-to-back or leased-line connection.
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Copyright © 2008 Yap Chin Hoong
yapchinhoong@hotmail.com