Hi Rene:
First of all, thanks for the lab. I'm trying to do it but I have some problemas with the tunneling. Could you put the routers configuration in order to check my solution?
Thanks in advance,
GRE Tunnel Basic
{difficulty}3{/difficulty}
Scenario:
You are working for Company "BigLabs" and you have heard some colleague network engineers talk about VPN tunnels and how they were unable to send routing protocols across the VPN tunnels. You also heard that a GRE tunnel could possible solve this problem. Let's see what this is all about and lab it up!
Goal:
- Configure all IP addresses as specified in the topology picture.
-
Configure a loopback interface on Router Godzilla and Nessie:
Godzilla: Loopback0: 1.1.1.1 /24
Nessie: Loopback0: 3.3.3.3 /24 - Configure EIGRP AS1 on all 3 routers, only advertise the 192.168.12.0 and 192.168.23.0 network, do not advertise the loopbacks.
- Ensure Router Godzilla and Nessie can ping each other.
- Configure a GRE tunnel between Router Godzilla and Nessie.
-
Configure the 192.168.13.0 /24 network on the GRE tunnel:
Godzilla: 192.168.13.1
Nessie: 192.168.13.3 - Ensure you can ping the IP addresses that you configured on the tunnel interface.
-
Configure another loopback interface on Router Godzilla and Nessie:
Godzilla: Loopback1: 11.11.11.11 /24
Nessie: Loopback1: 33.33.33.33 /24 - Configure OSPF and use network commands to advertise the network on the GRE tunnel.
- Advertise Loopback1 in OSPF on Router Godzilla and Nessie.
- Ensure you establish a OSPF neighbor relationship and that you see the loopback1 interfaces in the routing table.
IOS:
c3640-jk9s-mz.124-16.bin
Topology:
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Video Solution:
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Comments (13)
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usrah 2010-11-11 13:11:11
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ReneMolenaar 2010-11-26 18:38:44Hi Luis,
Do you still have your configs? drop them here and i'll take a look.
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ebalmon 2010-12-30 20:42:08Hi Rene, Thanks for the lab and congratulation for the page. Could you check it? If I can see the network 33.33.33.0/24 know by a OSPF update, I guess is work right? Thanks for your time
Godzilla#sh ip route
Gateway of last resort is not set
C 192.168.12.0/24 is directly connected, FastEthernet0/0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
C 192.168.13.0/24 is directly connected, Tunnel0
33.0.0.0/32 is subnetted, 1 subnets
O 33.33.33.33 [110/11112] via 192.168.13.3, 00
1:10, Tunnel0
D 192.168.23.0/24 [90/30720] via 192.168.12.2, 00:44:47, FastEthernet0/0
11.0.0.0/24 is subnetted, 1 subnets
C 11.11.11.0 is directly connected, Loopback1
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ReneMolenaar 2011-01-02 11:22:27
If you see the OSPF update you can assume it's working correctly. A better idea is to use some show and debug commands to confirm that it's actually working.
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venomriser 2011-03-06 11:01:10Rene,
i can up the tunnel. My line protocol stays down. any reason?
I used the fe interface as source.
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venomriser 2011-03-06 11:01:57
sorry, i can't bring up the tunnel.
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xtophe02 2011-05-05 11:58:56***********Godzilla************
host Godzilla
line con 0
logg sy
int f0/0
ip add 192.168.12.1 255.255.255.0
no sh
!
int l0
ip add 1.1.1.1 255.255.255.0
!router eigrp 1
netw 192.168.12.0 0.0.0.255
!
int tun 0
ip add 192.168.13.1 255.255.255.0
tu so f0/0
tu des 192.168.23.3
!
int l1
ip add 11.11.11.11 255.255.255.0
!
router ospf 1
!netw 192.168.12.0 0.0.0.255 are 0
netw 1.1.1.1 0.0.0.255 are 0
netw 11.11.11.11 0.0.0.255 are 0
netw 192.168.13.0 0.0.0.255 are 0
!
***********KingKong************host KingKong
line con 0
logg sy
int f0/0
ip add 192.168.12.2 255.255.255.0
no sh
int f1/0
ip add 192.168.23.2 255.255.255.0
no sh
!
router eigrp 1
netw 192.168.12.0 0.0.0.255
netw 192.168.23.0 0.0.0.255
!***********nessie********
host Nessie
line con 0
logg sy
int f0/0
ip add 192.168.23.3 255.255.255.0
no sh
!
int l0
ip add 3.3.3.3 255.255.255.0
!
router eigrp 1
netw 192.168.23.0 0.0.0.255
!
!
int tun 0
ip add 192.168.13.3 255.255.255.0
tu so f0/0
tu des 192.168.12.1
!
int l1
ip add 33.33.33.33 255.255.255.0
!
router ospf 1
!netw 192.168.23.0 0.0.0.255 are 0
netw 192.168.13.0 0.0.0.255 are 0
netw 3.3.3.3 0.0.0.255 are 0
netw 33.33.33.33 0.0.0.255 are 0
!
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ReneMolenaar 2011-10-07 11:05:09
Glad you like it!
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ersanka 2011-11-20 14:35:35Thanks for this Lab. Useful abd clear one for solid understanding.
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ReneMolenaar 2011-11-24 20:55:20
Thanks Ersan
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BS 2011-11-27 04:20:18Hi,
1) We have configured loop back 0 (1.1.1.1 and 3.3.3.3)but never used it in GRE-config. Is this loop back not required for GRE?.
2) On tunnel interfaces, we assigned IPs 192.168.13.1 and 192.168.13.3 but we never used that too so we can assign any random IPs on tunnel interface. Then why we have given that IP?
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ReneMolenaar 2011-12-09 21:00:04
On all the routers EIGRP is configured for basic connectivity. This way we can create a GRE tunnel between the two routers, otherwise they don't know how to reach each others IP address.
We use the IP addresses on the GRE tunnel so we can establish an OSPF adjacency between the two routers, the loopbacks are advertised in OSPF and learned through the GRE tunnel.