3Com Switch 8800 Advanced Software V5 Configuration Guide

Troubleshooting GRE 417
PC B run IPv4 and they are connected to each other via a GRE tunnel between
Switch 1 and Switch 2.
Figure 130 Troubleshoot GRE
Symptom: The interfaces at both ends of the tunnel are configured correctly and
can ping each other, but PC A and PC B cannot ping each other.
Solution:
■ On Switch 1 and Switch 2, carry out the display ip routing-table command in
any view respectively. On Switch 1, observe whether there is a route from itself
through Tunnel 1/0/0 to 10.2.0.0/16. On Switch 2, observe whether there is a
route from itself through Tunnel 1/0/0 to 10.1.0.0/16.
■ For any missing static routes, use the ip route-static command in system view
to configure.
PC A
10.1.1.1/16
PC B
10.2.1.1/16
Vlan-inter face 2
Vlan-inter face 1
Switch1 Switch3
Switch2
Tunnel 1/0/0 Tunnel 1/0/0
Internet
tunnel
PC A
10.1.1.1/16
PC B
10.2.1.1/16
Vlan-inter face 2
Vlan-inter face 1
Switch1 Switch3
Switch2
Internet
tunnel
PC A
10.1.1.1/16
PC B
10.2.1.1/16
Vlan-inter face 2
Vlan-inter face 1
Switch1 Switch3
Switch2
Internet
tunnel
PC A
10.1.1.1/16
PC B
10.2.1.1/16
Vlan-inter face 2
Vlan-inter face 1
Switch1 Switch3
Switch2
Tunnel 1/0/0 Tunnel 1/0/0
Internet
tunnel
PC A
10.1.1.1/16
PC B
10.2.1.1/16
Vlan-inter face 2
Vlan-inter face 1
Switch1 Switch3
Switch2
Internet
tunnel
PC A
10.1.1.1/16
PC B
10.2.1.1/16
Vlan-inter face 2
Vlan-inter face 1
Switch1 Switch3
Switch2
Tunnel 1/0/0 Tunnel 1/0/0
Internet
tunnel
PC A
10.1.1.1/16
PC B
10.2.1.1/16
Vlan-inter face 2
Vlan-inter face 1
Switch1 Switch3
Switch2
Internet
tunnel
PC A
10.1.1.1/16
PC B
10.2.1.1/16
Vlan-inter face 2
Vlan-inter face 1
Switch1 Switch3
Switch2
Internet
tunnel