Datasheet

Lab – Configuring a Point-to-Point GRE VPN Tunnel
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Addressing Table
Device
Interface
IP Address
Subnet Mask
Default Gateway
WEST
G0/1
172.16.1.1
255.255.255.0
N/A
S0/0/0 (DCE)
10.1.1.1
255.255.255.252
N/A
Tunnel0
172.16.12.1
255.255.255.252
N/A
ISP
S0/0/0
10.1.1.2
255.255.255.252
N/A
S0/0/1 (DCE)
10.2.2.2
255.255.255.252
N/A
EAST
G0/1
172.16.2.1
255.255.255.0
N/A
S0/0/1
10.2.2.1
255.255.255.252
N/A
Tunnel0
172.16.12.2
255.255.255.252
N/A
PC-A
NIC
172.16.1.3
255.255.255.0
172.16.1.1
PC-C
NIC
172.16.2.3
255.255.255.0
172.16.2.1
Objectives
Part 1: Configure Basic Device Settings
Part 2: Configure a GRE Tunnel
Part 3: Enable Routing over the GRE Tunnel
Background / Scenario
Generic Routing Encapsulation (GRE) is a tunneling protocol that can encapsulate a variety of network layer
protocols between two locations over a public network, such as the Internet.
GRE can be used with:
- Connecting IPv6 networks over IPv4 networks
- Multicast packets, such as OSPF, EIGRP, and streaming applications
In this lab, you will configure an unencrypted point-to-point GRE VPN tunnel and verify that network traffic is
using the tunnel. You will also configure the OSPF routing protocol inside the GRE VPN tunnel. The GRE
tunnel is between the WEST and EAST routers in OSPF area 0. The ISP has no knowledge of the GRE
tunnel. Communication between the WEST and EAST routers and the ISP is accomplished using default
static routes.
Note: The routers used with CCNA hands-on labs are Cisco 1941 Integrated Services Routers (ISRs) with
Cisco IOS Release 15.2(4)M3 (universalk9 image). The switches used are Cisco Catalyst 2960s with Cisco
IOS Release 15.0(2) (lanbasek9 image). Other routers, switches, and Cisco IOS versions can be used.
Depending on the model and Cisco IOS version, the commands available and output produced might vary
from what is shown in the labs. Refer to the Router Interface Summary Table at the end of this lab for the
correct interface identifiers.
Note: Make sure that the routers and switches have been erased and have no startup configurations. If you
are unsure, contact your instructor.
Instructor Note: Refer to the Instructor Lab Manual for the procedures to initialize and reload devices.