In this article, we provide a solution to connect your headquarters building (HQ) to any number of branch offices using industry-grade and free networking operating system and VPN protocols.
For this scenario we need:
Now let us assume and gather some information to start:
At each location grab a copy of VyOS network operating system depending on your platform:
At each location deploy an instance of VyOS accordingly:
$install image $poweroff
Note: the above is only for an ISO-based installation, the deployment method has already performed this
during deployment of OVA / IMA.
Initial Network Configuration
At each location make sure your VyOS instance has two network interfaces and power both on. Then, at each instance set the IP address for eth1 and eth2 and a default gateway respectively, for example at the HQ issue the following commands:
$ conf # set interface ethernet eth1 address 192.168.10.200/24 # set interface ethernet eth2 address 192.168.200.10/24 # set protocols static route 0.0.0.0/0 next-hop 192.168.10.254 # commit # save # exit $
Note: by issuing conf, you enter the configuration mode, by issuing commit you apply the changes from memory scratch space to working memory and by issuing save, you save them as the startup-config for later reboots. Finally, by exit, you go out of configuration mode.
Do the similar setup at other buildings with the relevant IPs and gateway addresses, for example at Building-2 use:
$ conf # set interface ethernet eth1 address 192.168.20.200/24 # set interface ethernet eth2 address 192.168.200.20/24 # set protocols static route 0.0.0.0/0 next-hop 192.168.20.254 # commit # save
Note: While not in configuration mode, you can ensure your settings by issuing show interfaces command to confirm the name and IP addresses assigned to the interfaces. You may also issue show IP route to ensure the effectiveness of your default gateway. You may even issue ping 18.104.22.168 to confirm an internet connection. If you are in configuration mode, you may issue those command by prefixing them with run such as run show interfaces.
You may prefer now to connect through ssh instead, so enable it by issuing the following command at the console:
$conf #set service ssh port '22' #commit
Generating and Transferring required keys
Wireguard protocol requires a pair of keys (private and public) for each connecting node. So at each location configuration mode:
$generate wireguard keypair
If you get some errors at the above step, make sure you have not booted from the Live CD by looking at the output of the following command:
Now you need the public key of HQ node at all branches as well as the public key of all branches be available at HQ node for further configuration, so print the keys and save a copy via ssh shell into your text editor for further usage:
$show wireguard pubkey
Configuring central listener at HQ
At HQ we need to enable listening for incoming connection on the UDP endpoint 22.214.171.124:12345. In configuration mode, issue the following commands:
#set interfaces wireguard wg10 address '192.168.200.10/24' #set interfaces wireguard wg10 port '12345' #set interfaces wireguard wg10 mtu '1280'
Note: You may find changing the MTU size suitable after initial setup for fine-tuning your deployment, hence you have it in the third line above at hand (You can also change Maximum Segment Size of the TCP protocol in conjunction, which is out of the scope of this document, but come back and read from here later).
Allowing each branch to connect
At the HQ router, for each incoming connection, you should create a peer by knowing its public key and allowing at least its tunnel address and one or more or a subnet of addresses at destination LAN in the relevant access list. To do this for example for Branch-2 ,issue the following commands at HQ router:
set interfaces wireguard wg10 peer Branch2 allowed-ips '192.168.200.20/32' set interfaces wireguard wg10 peer Branch2 allowed-ips '192.168.20.0/24' set interfaces wireguard wg10 peer Branch2 pubkey 'abcThePublicKeyStringofTheBranch2RouterIsHereXyz=' set interfaces wireguard wg10 peer Branch2 persistent-keepalive '15'
Note: Wireguard protocol is designed to be silent while nothing is transferred, but behind a NAT you may need a keep-alive to ensure the UDP mapping is not forgotten by the gateway router and is kept alive respectively.
Configuring connectors at branches
At each branch, you should initiate the connection to 126.96.36.199:12345 and allow at least the tunnel address of the HQ router and a portion or whole of the HQ LAN to travel through the tunnel. You should use the public key of the HQ node that you recorded previously. To configure, issue the following commands:
set interfaces wireguard wg20 peer HQ allowed-ips '192.168.10.0/24' set interfaces wireguard wg20 peer HQ allowed-ips '192.168.200.10/32' set interfaces wireguard wg20 peer HQ endpoint '188.8.131.52:12345' set interfaces wireguard wg20 peer HQ pubkey 'xyzThePublicKeyStringofTheCentralHQServerIsHereAbc=' set interfaces wireguard wg20 peer HQ persistent-keepalive '15'
Now we need to inform the router at each node to transfer traffic for other nodes to the tunnel address of the HQ. Similarly, at the HQ we need to inform the router to transfer traffic destined for each branch's LAN to the respective peer tunnel address in order to establish routing between Branch-2 and HQ we should do the following:
set protocols static route 192.168.20.0/24 next-hop 192.168.200.20
set protocols static route 192.168.10.0/24 next-hop 192.168.200.10
Optionally, if you want Branch-2, to see Branch-3 as well, add the following route:
set protocols static route 192.168.30.0/24 next-hop 192.168.200.10
And do not forget to allow Branch-3's traffic to travel through the tunnel with HQ by issuing:
set interfaces wireguard wg20 peer HQ allowed-ips '192.168.30.0/24'
Testing from LAN clients
At each LAN, the users may browse the internet using their default gateway, for example at HQ, each workstation has a default gateway set to 192.168.10.254. Now we need to set routing information in each client to inform them where to send the traffic destined for Branch-2, Branch-3, etc.
To do this, you may push and distribute the routes from your DHCP server at each LAN (out of the scope of this article), or you may set up a script to add the routes and specify the IP address of VyOS router at each location to handle the traffic of other locations. For example, at workstation-001 located in HQ LAN, the following commands should be run depending on their operating systems:
route add 192.168.20.0 mask 255.255.255.0 192.168.20.200 metric 1 /p
Note: The target computers on Branch-2 LAN should also have the route for reverse path added to them, if not you will only be able to see up to the routers and not the clients, hence add the reverse paths at destination nodes the same way depending on their OS:
up route add -net 192.168.10.0/24 gw 192.168.20.200 dev em1
Testing the results and expectations
Now you should be able to ping 192.168.20.2 (a server at branch-2) from workstation001 at HQ.
show interface wireguard wg10
show interface wireguard wg044
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