[Cisco] GRE Tunnel Tunnel
Description: company A's PC1 network segment 192.168.1.0 go 24 and company B's PC2 network segment 172.16.2.0 go 24 to establish GRE tunnel communication
Configuration ideas:
1. R1 and R2 should be able to communicate-- R1 and R2 should respectively configure a default route to ISP
2. Create a new tunnel port, set IP, and the two sides should be in the same network segment; configure source, that is, public network egress IP and destination, that is, each other's public network egress ip
3. The tunnel of both parties has been established and a route needs to be established. The configuration of the PC1 network segment to the PC2 network segment, the PC2 network segment to the PC1 network segment and the next hop address to the peer ip; ends at this time.
The topology diagram is as follows:
Configuration Information:
R1:
Config t
Ip route 0.0.0.0 0.0.0.0 100.1.1.2
Int g0/1
No sh
Ip add 100.1.1.1 255.255.255.252
Exit
Int f0/1
No sh
Ip add 192.168.1.1 255.255.255.0
Exit
Int tunnel 0
No sh
Ip add 10.10.10.1 255.255.255.0
Tunnel source 100.1.1.1
Tunnel destination 200.2.2.2
Tunnel mode gre ip
Exit
Ip route 172.16.2.0 255.255.255.0 10.10.10.2
Exit
ISP:
Config t
Int g0/1
No sh
Ip add 100.1.1.2 255.255.255.252
Exit
Int g0/2
No sh
Ip add 200.2.2.1 255.255.255.252
Exit
R3:
Config t
Ip route 0.0.0.0 0.0.0.0 200.2.2.1
Int g0/2
No sh
Ip add 200.2.2.2 255.255.255.252
Exit
Int f0/1
No sh
Ip add 172.16.2.1 255.255.255.0
Exit
Int tunnel 0
No sh
Ip add 10.10.10.2 255.255.255.0
Tunnel source 200.2.2.2
Tunnel destination 100.1.1.1
Tunnel mode gre ip
Exit
Ip route 192.168.1.0 255.255.255.0 10.10.10.2
Exit
You need to check the process of ping. You can open debug and debug ip packet
