Now that we've entered a basic configuration on Vyatta VC4 VMs and made sure that we do not have connectivity problems, we can proceed and test the GRE and IPIP tunnels in case of Scenario 1. If you do not recall what was Scenario 1 take a look here.
First we will configure them without IPsec protection to see how they behave. Since we are in our private lab, security is not a problem. I suppose I do not have to remind you that, in practice, if you simply first configure the GRE or IPIP tunnels without IPsec protection to make sure that they are up and working, *anybody* with access to the wire can hack into your network (the portion of it accessible through the tunnels).

Actually I want to point out an aspect: Vyatta really shines in a particular area: if you have to do a deployment in practice, you can actually do so having a working and tested configuration. First you can easily do the tests using a VMware lab for example, find a working configuration and optimize this configuration. Then, with the confidence gained over your configuration files, deployment should be easy and trouble free.
And the branch office admins can be provided with a fully workable configuration file to enter on their Vyatta machines.
These aspects are quite important because they can save time and money.

As in Part 5, I will enable VMware Network AdapterVMnet5, see Figure71.

Figure71: VMware Network Adapter VMnet5 Enabled

And before entering the configuration lines on the Vyatta VC4 machines, I will start a Wireshark capture on the VMnet5 interface on the host machine(see Figure72, make sure "Capture packets in promiscous mode " is selected) . Doing so, I will have central point of view over the traffic sent between Vyatta VC4 machines, I will see the first packets sent through the tunnels, the OSPF multicast packets and so on. This is very useful for troubleshooting and we can actually see how things work.

Figure72: Start a Wireshark capture on the VMnet5 interface on the host machine

And we will run OSPF through these tunnels to discover the networks behind the other Vyatta VC4 machines.

set protocols ospf area 100
set protocols ospf area 100 network 192.168.10.0/24
set protocols ospf area 100 network 192.168.111.0/24
set protocols ospf area 100 network 192.168.121.0/24
set protocols ospf log-adjacency-changes
commit

And we will run OSPF through this tunnel to discover the networks behind the other Vyatta VC4 machines.

set protocols ospf area 100
set protocols ospf area 100 network 192.168.30.0/24
set protocols ospf area 100 network 192.168.111.0/24
set protocols ospf log-adjacency-changes
commit

And we will run OSPF through this tunnel to discover the networks behind the other Vyatta VC4 machines.

set protocols ospf area 100
set protocols ospf area 100 network 192.168.40.0/24
set protocols ospf area 100 network 192.168.121.0/24
set protocols ospf log-adjacency-changes
commit

If we take a look at the Wireshark capture, we will notice that it recorded some activity, a sign that our tunnels are working. In Figure73 we can spot OSPF traffic sent through the GRE tunnel between HQ and Branch1.

Figure73: Wireshark Capture GRE Tunnels: OSPF Traffic

Let's check the routing table on the Vyatta HQ, Vyatta Branch1 and Vyatta Branch2, see Figure74, Figure75 and Figure76 . We can notice that every Vyatta VC4 machine is now aware of the networks behind the other Vyatta VC4 machines.

Figure74: Vyatta HQ GRE Tunnels: Routing Table

Figure75: Vyatta Branch1 GRE Tunnels: Routing Table

Figure76: Vyatta Branch2 GRE Tunnels: Routing Table

Figure77: Vyatta HQ GRE Tunnels: show ip ospf interface tun1 and tun2

Figure78: Vyatta Branch1 GRE Tunnels: show ip ospf interface tun1

Figure79: Vyatta Branch2 GRE Tunnels: show ip ospf interface tun1

Let's see if we have connectivity between hosts located behind Vyatta VC4 machines, see Figure80, Figure81 and Figure82.

Figure80: GRE Tunnels: Ping from a Host Behind Vyatta HQ to Hosts Behind Vyatta Branch1 and Vyatta Branch2

Figure81: GRE Tunnels: Ping from a Host Behind Vyatta Branch1 to Hosts Behind Vyatta HQ and Vyatta Branch2

Figure82: GRE Tunnels: Ping from a Host Behind Vyatta Branch2 to Hosts Behind Vyatta HQ and Vyatta Branch1

The ping traffic we generated was recorded by our Wireshark capture, see Figure83.

Figure83: Wireshark Capture GRE Tunnels: Ping

Things look good.

All the configuration lines entered on Vyatta HQ, Vyatta Branch1 and Vyatta Branch2 can be found here:
 - Vyatta HQ
 - Vyatta Branch1
 - Vyatta Branch2

If you want, you can make the hub-and-spoke topology a mesh one, by configuring a point-to-point GRE tunnel between Branch1 and Branch2.

On Branch1 add:

set interfaces tunnel tun2
set interfaces tunnel tun2 address 192.168.131.1/24
set interfaces tunnel tun2 description "Gre Tunnel to Branch2"
set interfaces tunnel tun2 encapsulation gre
set interfaces tunnel tun2 local-ip 192.168.50.3
set interfaces tunnel tun2 remote-ip 192.168.50.4

set protocols ospf area 100 network 192.168.131.0/24

On Branch2 add:

set interfaces tunnel tun2
set interfaces tunnel tun2 address 192.168.131.2/24
set interfaces tunnel tun2 description "Gre Tunnel to Branch1"
set interfaces tunnel tun2 encapsulation gre
set interfaces tunnel tun2 local-ip 192.168.50.4
set interfaces tunnel tun2 remote-ip 192.168.50.3

set protocols ospf area 100 network 192.168.131.0/24

And we will run OSPF through these tunnels to discover the networks behind the other Vyatta VC4 machines.

set protocols ospf area 100
set protocols ospf area 100 network 192.168.10.0/24
set protocols ospf area 100 network 192.168.111.0/24
set protocols ospf area 100 network 192.168.121.0/24
set protocols ospf log-adjacency-changes
commit

And we will run OSPF through this tunnel to discover the networks behind the other Vyatta VC4 machines.

set protocols ospf area 100
set protocols ospf area 100 network 192.168.30.0/24
set protocols ospf area 100 network 192.168.111.0/24
set protocols ospf log-adjacency-changes
commit

And we will run OSPF through this tunnel to discover the networks behind the Vyatta VC4 machines.

set protocols ospf area 100
set protocols ospf area 100 network 192.168.40.0/24
set protocols ospf area 100 network 192.168.121.0/24
set protocols ospf log-adjacency-changes
commit