Panasonic NN46240-710 - Manual (Page 65)

Nortel Secure Router 8000 Series
Troubleshooting - VPN___________ 2 GRE troubleshooting
• PCs cannot ping through each other although tunnel interfaces on two ends can ping each
other successfully
2.3.1 Ping of the peer tunnel fails although the network layer
protocols on both ends are up
Fault symptom
Figure 2-5 Networking diagram of the GRE troubleshooting I
Loopbacki
1.1.1.1/32
Loopbacki
2.2.2.2/32
Nortell K b
Nortel2
Tunnel1/0/0
11.1.1.1/24
Tunnel1/0/0
21.1.1.1/24
The network layer protocols on both ends of the GRE tunnel are up. But, Tunnel 1/0/0 on Nortel
1 and Tunnel 1/0/0 on Nortel 2 cannot ping through each other.
Fault analysis
The possible causes are as follows:
• The GRE keys on both ends are inconsistent.
• The IP addresses of the tunnel interfaces on two ends are not in the same network segment
and no reachable route exists between two ends of the tunnel
Use the display interface tunnel interface-number command on both ends to check whether
the GRE keys are consistent.
The output of the command on Nortel 1 is as follows:
[Nortell] display interface Tunnel 1/0/0
Tunnel1/0/0 current state : UP
Line protocol current state : UP
Description : Nortel Series, Tunnell/0/0 Interface
The Maximum Transmit Unit is 1000 bytes
Internet Address is 11.1.1.1/24
Encapsulation is TUNNEL, loopback not set
Tunnel source 1.1.1.1 (LoopBack1), destination 2.2.2.2
Tunnel protocol/transport GRE/IP , key 0x2
linkalive disabled
Checksumming of packets disabled
QoS max-bandwidth : 64 Kbps
Output queue
Output queue
Output queue
(Urgent queue : Size/Length/Discards) 0/50/0
(Protocol queue : Size/Length/Discards) 0/1000/0
(FIFO queuing : Size/Length/Discards) 0/256/0
5 minutes input rate 0 bytes/sec, 0 packets/sec
Issue 5.3 (30 March 2009) Nortel Networks Inc. 2-11