CCNA 4 WAN

Cork24

studying CCNA in College and going over a few past papers..

One Question

A network administrator has configured a PPP link on her company’s WAN, but users packets are not routed across the link. Describe the checks she should do to troubleshoot the connection and what the possible causes could be.

my Answer would be,
1. Check IP Route.
2. Check to see is PAP/Chap on both Routers
3. Make sure Both Routers have The Other Routers Username & Password.

possible cause could that PAP is on one Router and chap is on the other, the routers could have their own Username & Password set but not the Router their connected to.

Next Question

Given the following topology and configuration extracts, identify the mistakes in the configurations.

R1 is Connected by Serial port to R3

hostname R1
username R3 password R3pass
int serial 0/0 ip address 128.0.1.2 255.255.255.252
encapsulation ppp
ppp authentication pap
ppp callback request
ppp pap sent-username R3 password

hostname R3
username R1 password R1pass
int serial 0/1 ip address 128.0.1.2 255.255.255.252
encapsulation ppp
ppp authentication chap ppp
pap sent-username R1 password R1pass
R3pass

my Answer from what i see is, both S0/0 & S0/1 have the same IP Address. they have authentication set up as CHAP on Router 3 & PAP on Router 1, "pap sent-username R1 password R1" (Dont know what this Config does)

would their be right answers or can some one else shine light ?

nljm25

Cork24 wrote: »

studying CCNA in College and going over a few past papers..

One Question

A network administrator has configured a PPP link on her company’s WAN, but users packets are not routed across the link. Describe the checks she should do to troubleshoot the connection and what the possible causes could be.

my Answer would be,
1. Check IP Route.
2. Check to see is PAP/Chap on both Routers
3. Make sure Both Routers have The Other Routers Username & Password.

Check the phyiscal layer (cable types/clocking etc) first like using sh int to ensure the WAN link in up/up and then that check the IPs at both ends are on the same subnet. The others (1/2/3) are good as next steps.:)

possible cause could that PAP is on one Router and chap is on the other, the routers could have their own Username & Password set but not the Router their connected to.

Next Question

Given the following topology and configuration extracts, identify the mistakes in the configurations.

R1 is Connected by Serial port to R3

hostname R1
username R3 password R3pass
int serial 0/0 ip address 128.0.1.2 255.255.255.252
encapsulation ppp
ppp authentication pap
ppp callback request
ppp pap sent-username R3 password

hostname R3
username R1 password R1pass
int serial 0/1 ip address 128.0.1.2 255.255.255.252
encapsulation ppp
ppp authentication chap ppp
pap sent-username R1 password R1pass
R3pass

my Answer from what i see is, both S0/0 & S0/1 have the same IP Address. they have authentication set up as CHAP on Router 3 & PAP on Router 1, "pap sent-username R1 password R1" (Dont know what this Config does)
would their be right answers or can some one else shine light ?

The pap sent-username is an configuration alternative to what is normally sent i.e. the hostname. This should give you some insight into what else is incorrect.

Cork24

Check the phyiscal layer (cable types/clocking etc) first like using sh int to ensure the WAN link in up/up and then that check the IPs at both ends are on the same subnet. The others (1/2/3) are good as next steps.:)

didnt think of the physical layer, as my though was it was just the config Wrong but being good practice, you should state every thing, from is the Router turned on.. Cheers