CCNA Notes
CompTIA LX103
Cisco ICND1
Cisco ICND2
Cisco CCNP Route
Various
Labs
CompTIA LX103
Cisco ICND1
Cisco ICND2
Cisco CCNP Route
Various
Labs
Generic Routing Encapsulation protocol can be used as logical point-to-point links, encapsulating most any traffic over a tunnel as unicast. The unicast feature being useful over IPSEC as IPSEC only works over unicast traffic.
Assuming all destinations are routable
– creating a basic GRE Tunnel
over the following topology:
Simple Topology–
R1–
R1#conf t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#int tunnel 100 R1(config-if)#tunnel source loopback 0 R1(config-if)#tunnel destination 10.35.0.1 *Mar 1 00:01:05.803: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel100, changed state to up
R3–
R3#conf t Enter configuration commands, one per line. End with CNTL/Z. R3(config)#interface tunnel 100 R3(config-if)#ip address 172.16.0.2 255.255.255.252 R3(config-if)#tunnel source loopback 0 R3(config-if)#tunnel destination 10.15.0.1 *Mar 1 00:12:56.219: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel100, changed state to up
Gateway of last resort is not set 172.16.0.0/30 is subnetted, 1 subnets C 172.16.0.0 is directly connected, Tunnel100 10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks C 10.10.0.0/24 is directly connected, FastEthernet0/0 C 10.15.0.1/32 is directly connected, Loopback0 O 10.20.0.0/24 [110/20] via 10.10.0.2, 00:11:28, FastEthernet0/0 O 10.35.0.1/32 [110/21] via 10.10.0.2, 00:11:28, FastEthernet0/0 R1#ping 172.16.0.2 <-- R3 Tu100 interface Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.16.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 12/22/32 ms R1#traceroute 172.16.0.2 <-- R3 Tu100 interface Type escape sequence to abort. Tracing the route to 172.16.0.2 1 172.16.0.2 44 msec 40 msec 40 msec R1#traceroute 10.35.0.1 <-- R3 Lo0 interface Type escape sequence to abort. Tracing the route to 10.35.0.1 1 10.10.0.2 40 msec 8 msec 12 msec 2 10.20.0.2 16 msec 36 msec 24 msec