1.Client is unable to ping R1’s serial interface from the client.
Problem was disable authentification on R1, check where authentication is not given under router ospf of R1. (use ipv4 Layer 3)
Configuration on R1 was:
interface Serial0/0/0/0.12 point-to-point
ip address 10.1.1.1 255.255.255.252
ip nat inside
ip ospf message-digest-key 1 md5 TSHOOT
!
router ospf 1
log-adjacency-changes
network 10.1.1.0 0.0.0.3 area 12
default-information originate always
Configuration on R2 was:
interface Serial0/0/0/0.12 point-to-point
ip address 10.1.1.2 255.255.255.252
ip ospf authentication message-digest
ip ospf message-digest-key 1 md5 TSHOOT
!
router ospf 1
log-adjacency-changes
network 10.1.1.0 0.0.0.3 area 12
Answer: on R1 need command in router mode
area 12 authentication message-digest
Ans1) R1
Ans2) OSPF
Ans3) ip ospf authentication message-digest command must be given on s0/0/0/0.12
