1. Net 412 (Practical Part)
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LAB 2

2. Configuring Point-to-Point GRE VPN Tunnels
Generic Routing Encapsulation (GRE) is a tunneling protocol developed by Cisco that allows the encapsulation of a wide variety of network layer protocols inside point-to-point links.
A GRE tunnel is used when packets need to be sent from one network to another over the Internet or an insecure network. With GRE, a virtual tunnel is created between the two endpoints (Cisco routers) and packets are sent through the GRE tunnel.
It is important to note that packets travelling inside a GRE tunnel are not encrypted as GRE does not encrypt the tunnel but encapsulates it with a GRE header. If data protection is required, IPSec must be configured to provide data confidentiality – this is when a GRE tunnel is transformed into a secure VPN GRE tunnel
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3. Part 1: Configure Networks :
Open the packet tracer.
Add 2-laptops, 2-switch general-pt,3 3-router
Link all the devices together type of link copper cross .
Links between R1 and R3 , R3 and R2 are copper cross ovell
Configure Ip address for all Network like topology above
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4. Topology
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5. Configure pc 0
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6. Configure R1
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7. Configure R1
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8. Configure R3
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9. Configure R3
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10. Configure R2
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11. Configure R2
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12. Configure pc 1
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13. Show Ip route Networks and Communication Department
Router 3 has no idea about networks and
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14. Part 2: Configure GRE Tunnel on Router 1
R1>en R1#config t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#int tunnel 0 R1(config-if)#ip address R1(config-if)#tunnel source g0/1 R1(config-if)#tunnel destination R1(config-if)#tunnel mode gre ip R1(config-if)#ex R1(config)#ip route R2(config)#ip route g0/1 R1(config)#do wri
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15. Part 2: Configure GRE Tunnel on Router 1
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16. Cont. Part 2: Configure GRE Tunnel on Router 1
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17. Part 3: Configuring GRE Tunnel on Router 2(private Network):
R2>en
R2#config t
Enter configuration commands, one per line. End with CNTL/Z.
R2(config)#int tunnel 0
R2(config-if)#
%LINK-5-CHANGED: Interface Tunnel0, changed state to up
R2(config-if)#ip address
R2(config-if)#tunnel source g0/1
R2(config-if)#tunnel destination
R2(config-if)#tunnel mode gre ip
R2(config-if)#ex
R2(config)#ip route
R2(config)#ip route g0/1
R2(config)#do wri
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18. Part 3: Configuring GRE Tunnel on Router 2(private Network):
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19. Part 4: Tracing the path of networks connected , Use command show ip route
R1#show ip route
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20. Part 4
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21. Part 4
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22. Part 5:
After configuring tunnel, two tunnel endpoints can see each other can verify using an ICMP echo from one end
Ping pc-0 from pc-1
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23. Part 5
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24. Part 5
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25. Part 6: use the simulation panel to trace the packet movement.
Now both networks ( /24 and /24) are able to freely communicate with each other over the GRE Tunnel .
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26. Part 6
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27. The End
Any Questions ?
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