WireGuard Site-to-Site VPN Configuration Example¶

This recipe explains how to setup a VPN tunnel between two firewalls using WireGuard.

This example is a minimal configuration, more complicated scenarios are possible, see WireGuard for details.

Required Information¶

General Values

Item	Value
Design	Site-to-Site, one peer per tunnel
Tunnel Subnet	`10.6.210.0/24`

HQ:

Item	Value
WAN IP Address	`198.51.100.15`
Tunnel Address	`10.15.210.1/24`
Listen Port	`51820`
LAN Subnet	`10.15.0.0/24`

Satellite Office:

Item	Value
WAN IP Address	`198.51.100.23`
Tunnel Address	`10.15.210.2/24`
Listen Port	`51820`
LAN Subnet	`10.23.0.0/24`

Tunnel Configuration¶

First create the WireGuard tunnel on both sites:

Navigate to VPN > WireGuard
Click Add Tunnel
Fill in the options using the information determined earlier, with variations noted for each site:

Enabled

Checked

HQ Settings

Description

Satellite Office VPN

Address

10.15.210.1/24

Satellite Office Settings

Description

HQ VPN

Address

10.15.210.2/24

Listen Port

51820

Interface Keys

Click Generate to create a new set of keys.
Copy the public key from each firewall and note which is which
Click Save

Peer Configuration¶

The peer entry for the server can be added when editing the tunnel. Follow these steps on both sites, with the differences in settings noted inline.

Edit the tunnel:

Navigate to VPN > WireGuard
Locate the WireGuard tunnel for this VPN provider
Click at the end of the row for the tunnel

From the tunnel editing page, add a peer:

Click Add Peer
Fill in the options using the information determined earlier:

HQ Settings

Description

Satellite Office Peer

Endpoint

198.51.100.23 (the WAN IP address of the Satellite Office)

Endpoint Port

51820

Public Key

The public key from the Satellite Office firewall

Allowed IPs

10.15.210.2/32, 10.23.0.0/24 (Satellite office tunnel address and LAN)

Peer WireGuard Address

10.15.210.2 (Satellite office tunnel address)

Satellite Office Settings

Description

HQ VPN Peer

Endpoint

198.51.100.15 (the WAN IP address of HQ)

Endpoint Port

51820

Public Key

The public key from the HQ firewall

Allowed IPs

10.15.210.1/32, 10.15.0.0/24 (HQ tunnel address and LAN)

Peer WireGuard Address

10.15.210.1 (HQ tunnel address)
Click Update
Click Save

Assign Interface¶

These steps should be done on both sites.

First, fix the default gateway so WireGuard isn’t automatically selected before it’s ready:

Navigate to System > Routing
Set Default Gateway IPv4 to a specific gateway (e.g. WANGW) or group
Set Default Gateway IPv6 in a similar manner if this VPN will also carry IPv6 traffic
Click Save
Click Apply Changes

Next, assign the interface so the automatic gateway can be used for policy routing (Assign a WireGuard Interface).

Navigate to Interfaces > Assignments
Select the appropriate wg<number> interface in the Available network ports list
Click Add to assign the interface as a new OPT interface (e.g. OPT1)
Navigate to the Interface configuration page, Interfaces > OPTx
Check Enable
Enter an appropriate Description which will become the interface name (e.g. VPN_HQ or VPN_Satellite)
Click Save
Click Apply Changes

Firewall Rules¶

First, add a rule to the WAN on both firewalls to allow traffic to reach WireGuard:

Navigate to Firewall > Rules, WAN tab
Click Add to create a new firewall rule at the top of the list so that it matches before other rules
Configure the firewall rule as follows:

Action

Pass

Protocol

UDP

Source

This can typically be left at Any, but it is more secure to fill in the IP address of the opposing firewall.

Destination

WAN Address

Destination Port Range

(other), 51820

Description

Pass traffic to WireGuard
Click Save
Click Apply Changes

Next, add a rule to pass traffic inside the WireGuard tunnel on both firewalls:

Navigate to Firewall > Rules
Click the tab for the assigned WireGuard interface (e.g. VPN_Satellite or VPN_HQ)
Click Add to add a new rule to the top of the list
Use the following settings:

Action

Pass

Protocol

Any

Source

any

Destination

any

Description

Pass VPN traffic from WireGuard peers

Note

This rule allows all traffic between sites, which is easy but not a secure practice. Traffic between the sites can be restricted as needed with less permissive rules.
Click Save
Click Apply Changes

Routing¶

Since the networks for the peers were entered in the Allowed IPs field, the firewall will automatically handle setting up routes to the peer, so no additional routing work should be needed.

Finish Up¶

The configuration is now complete! The two sites should now have full LAN-to-LAN connectivity.