Set up a VPN Between Two Fireware Devices (WSM)

A branch office virtual private network (BOVPN) tunnel is a secure way for networks, or for a host and a network, to exchange data across the Internet. This document tells you how to use Policy Manager to define a manual BOVPN tunnel between two Fireboxes.

For the same example as configured in Fireware Web UI, go to Set up a VPN Between Two Fireware Devices (Web UI).

For detailed information about BOVPN settings, go to:

Determine IP Address and Tunnel Settings

Before you create a manual BOVPN tunnel, we recommend that you determine which IP addresses and settings to use. This topic includes a checklist that can help you plan.

In this example, both endpoints have static external IP addresses. For information on BOVPN tunnels to devices with a dynamic external IP address, go to Define Gateway Endpoints for a BOVPN Gateway.

Make sure that you configure the VPN endpoints correctly and that the Phase 1 and Phase 2 settings are the same on both Fireboxes. The VPN tunnel does not build if the settings do not match.

If a setting does not appear in this list, keep the default value for that setting.

BOVPN Tunnel Settings

Site A Firebox

Public IP address: ______________________________

Private IP address: _____________________________

Site B Firebox

Public IP address: ______________________________

Private IP address: _____________________________

Phase1 Settings

Both Fireboxes must use exactly the same values.

For a BOVPN tunnel between two Fireboxes, we recommend that you select Dead Peer Detection (RFC3706), not IKE Keep-Alive. Do not select both. You should always select Dead Peer Detection if both endpoint devices support it.

Credential method: Select Use Pre-Shared Key.

Pre-shared key: ______________________________

(Fireware v12.5.4 or higher) Pre-shared key type (string-based or hex-based): ________________

IKE Version: IKEv1 ____ IKEv2 ____

Mode (choose one): Main ____ Aggressive ____

NAT Traversal: Yes ____ No ____

NAT Traversal Keep-alive interval: ________________

IKE Keep-alive: Yes ____ No ____

IKE Keep-alive Message interval: ________________

IKE Keep-alive Max failures: ________________

Dead Peer Detection (RFC3706): Yes ____ No ____

Dead Peer Detection Traffic idle timeout: ________________

Dead Peer Detection Max retries: ________________

Authentication algorithm (choose one): MD5___SHA1____ SHA2-256____SHA2-384____SHA2-512____
We recommend SHA-1 or SHA-2

Encryption algorithm (choose one): DES____ 3DES____ AES-128____ AES-192____ AES-256____ AES-GCM-128____AES-GCM-192____AES-GCM-256
We recommend an AES variant. AES-GCM is supported in Fireware v12.2 or higher. AES-GCM is supported for IKEv2 only.

SA Life ________________

Select Hours as the unit for SA life.

Diffie-Hellman Group (choose one): 1____ 2____ 5____14____15____19____20____

Phase 2 Settings

Both Fireboxes must use exactly the same values.

Perfect Forward Secrecy (Diffie-Hellman Group): Disable____ Group1____ Group2____ Group5____ Group14____ Group15____ Group19____ Group20____

Authentication algorithm (choose one): MD5___SHA1____ SHA2-256____SHA2-384____SHA2-512_____ (We recommend SHA-1 or SHA-2)

Encryption algorithm (choose one): DES____ 3DES____AES-128____ AES-192____ AES-256____ AES-GCM-128____AES-GCM-192____AES-GCM-256
We recommend an AES variant. AES-GCM is supported in Fireware v12.2 or higher. AES-GCM is supported for ESP only.

Force Key Expiration Time (Hours): ________________

Force Key Expiration Traffic (kilobytes): ________________

Example Tunnel Settings

This section has the same fields as the previous section, and includes example settings. These settings correspond to the settings that appear in the images in this example.

Site A Firebox

Public IP address: 203.0.113.2

Private network IP address: 10.0.1.0/24

Site B Firebox

Public IP address: 198.51.100.2

Private network IP address: 10.50.1.0/24

Phase 1 Settings

Both sides must use exactly the same values.

Credential method: Select Use Pre-Shared Key.

Pre-shared key: [Specify a strong key]

Pre-shared key type: String-based

Version: IKEv1

Mode: Main

NAT Traversal: Enable

NAT Traversal Keep-alive interval: 20 seconds

IKE Keep-alive: Disable

IKE Keep-alive Message interval: none

IKE Keep-alive Max failures: none

Dead Peer Detection (RFC3706): Enable

Dead Peer Detection Traffic idle timeout: 20 seconds

Dead Peer Detection Max retries: 5

Authentication algorithm: SHA256

Encryption algorithm: AES (256-bit)

SA Life: 24 hours

Diffie-Hellman Group: 14

Phase 2 Settings

Both sides must use exactly the same values.

Perfect Forward Secrecy (Diffie-Hellman Group): 14

Type: ESP

Authentication algorithm: SHA256

Encryption algorithm: AES (256-bit)

Configure Site A

You now use Policy Manager to configure the gateway on the Site A Firebox. A gateway is a connection point for one or more tunnels. To configure a gateway, you must specify:

Credential method (either pre-shared keys or an IPSec Firebox certificate)
Location of local and remote gateway endpoints, either by IP address or domain information
Settings for Phase 1 of the Internet Key Exchange (IKE) negotiation

Add a VPN Gateway

Select VPN > Branch Office Gateways.
The Gateways dialog box appears.
Click Add.
The New Gateway dialog box appears.

Screen shot of the New Gateway dialog box

In the Gateway Name text box, type a name to identify this gateway in Policy Manager.
In the Credential Method area, select Use Pre-Shared Key.
(Fireware v12.5.4 or higher) Select String-Based or Hex-Based. The default setting is String-Based. For information about hex-based keys, go to Hex-Based Pre-Shared Keys.
Type the shared key.
The shared key must use only standard ASCII characters.
In the Gateway Endpoints section, click Add.
The New Gateway Endpoints Settings dialog box appears.

Screen shot of the New Gateway Endpoints Settings for Site A to Site B

From the External Interface drop-down list, select the interface that has the external (public) IP of the Site A Firebox.
(Fireware v12.2 or higher) To specify an IP address, in the Interface IP Address drop-down list, select Primary Interface IP Address or select a secondary IP address that is already configured on the selected external interface. Tip!
Select By IP Address and type the primary IP address of the Firebox interface.
In Fireware v12.4 or higher, you must specify an IP address type that matches the Address Family setting you configured earlier. For example, if you specified IPv6 Addresses, you must specify an IPv6 address in the By IP Address text box.
In the Remote Gateway section, select Static IP Address.
In the adjacent text box, type the external (public) IP address of the Site B Firebox.
Select By IP Address.
In the adjacent text box, type the external (public) IP address of the Site B Firebox.
Click OK.

Screen shot of the New Gateway dialog box with gateway endpoints defined

For information about the Use modem for failover setting, go to Configure VPN Modem Failover.

For information about the Start Phase 1 tunnel when Firebox startssetting, go to Disable Automatic Tunnel Startup.

Configure the Phase 1 Settings

Phase 1 of establishing an IPSec connection is where the two peers make a secure, authenticated channel they can use to communicate. This is known as the ISAKMP Security Association (SA).

Select the Phase 1 Settings tab.

Screen shot of the New Gateway dialog box - Phase 1 Settings for Site A

From the Mode drop-down list, select Main.
The example uses Main Mode because both endpoints have static IP addresses. If one endpoint has a dynamic IP address, you must use Aggressive mode.
Select NAT Traversal, which we recommended for a BOVPN tunnel between two Fireboxes.
NAT Traversal, or UDP Encapsulation, allows traffic to get to the correct destinations when a device does not have a public IP address.
Dead Peer Detection (RFC3706), which we recommended for a BOVPN tunnel between two Fireboxes.
When you enable dead peer detection, the Firebox connects to a peer only if no traffic is received from the peer for a specified length of time and a packet is waiting to be sent to the peer. This method is more scalable than IKE keep-alive messages.
In the Transform Settings area, select the default transform and click Edit.

Screen shot of the Phase 1 Transform dialog box with default values.

From the Authentication and Encryption drop-down lists, select your preferred algorithm. In our example, we use SHA256 and AES (256-bit).
In the SA Life text box, type 24 and select Hours.
The security association (SA) is valid for the amount of time that you specify in this setting. If the two VPN gateways do not complete Phase 2 negotiations before the Phase 1 SA expires, then they must complete Phase 1 negotiations again.
From the Key Group drop-down list, select a Diffie-Hellman group. In our example, we select Diffie-Hellman Group 14.
Diffie-Hellman (DH) groups determine the strength of the key used in the key exchange process.
Click OK. Leave all other Phase 1 settings with their default values.
Click OK.
The gateway you added appears in the Gateways list.

Screen shot of the Gateways dialog box for Site A

Click Close to close the Gateways dialog box.

For more information about IPSec VPN negotiations, go to About IPSec VPN Negotiations.

For more information about Diffie-Hellman groups, go to About Diffie-Hellman Groups.

Add a VPN Tunnel

After you define gateways, you can make tunnels between them. The process for making a tunnel includes:

Specify routes (local and remote endpoints for the tunnel)
Configure Phase 2 of the Internet Key Exchange (IKE) negotiation

From Policy Manager:

Select VPN > Branch Office Tunnels.
The Branch Office IPSec Tunnels dialog box appears.
Click Add.
The New Tunnel dialog box appears.

Screen shot of the New Tunnel dialog box

In the Tunnel Name text box, type a name for the tunnel.
From the Gateway drop-down list, select the gateway you just created.
Select the Add this tunnel to the BOVPN-Allow policies check box at the bottom of the dialog box if you want to add the tunnel to the BOVPN-Allow.in and BOVPN-Allow.out policies. These policies allow all traffic that matches the tunnel routes. If you want to restrict traffic through the tunnel, clear this check box and use the BOVPN Policy Wizard to create policies for types of traffic that you want to allow through the tunnel. For more information, go to Define Custom Tunnel Policies.
In the Addresses area, click Add.
The Tunnel Route Settings dialog box appears.

Screen shot of the Tunnel Route Settings dialog box for Site A configuration

In the Local and Remote sections, configure one of these options to specify which devices behind the local Firebox can communicate through the tunnel.

(Fireware v12.3.1 or lower) Type an IPv4 address in the text box.
(Fireware v12.4 or higher) Type an IPv4 or IPv6 address in the text box.
The IP address you specify must be of the same address family (IPv4 or IPv6) as the gateway.
Click the button adjacent to the Local drop-down list to specify a host IP address, network address, range of host IP addresses, or a host name.
For IPv6, if you select Host Name, your local computer must be able to resolve the host name to an IPv6 address.
(Fireware v12.4 or higher) Select the Any IPv4 or Any IPv6 box to specify a zero route (0.0.0.0/0 or ::/0).

From the Direction drop-down list, click the tunnel direction. The tunnel direction determines which endpoint of the VPN tunnel can start a VPN connection through the tunnel.
Click OK.
The tunnel route appears in the Addresses tab of the New Tunnel dialog.

Screen shot of the New Tunnel dialog box for tunnel to Site B

Configure the Phase 2 Settings

Phase 2 settings include settings for a security association (SA), which defines how data packets are secured when they are passed between two endpoints. The SA keeps all information necessary for the Firebox to know what it should do with the traffic between the endpoints.

From the New Tunnel dialog box, select the Phase 2 Settings tab.

Screen shot of the New Tunnel, Phase 2 Settings for Site A

Select the PFS check box to enable Perfect Forward Secrecy (PFS).
PFS makes keys more secure because new keys are not made from previous keys. If a key is compromised, new session keys are still secure. When you specify PFS during Phase 2, a Diffie-Hellman exchange occurs each time a new SA is negotiated.
Select a Diffie-Hellman Group from the drop-down list. In our example, we select Diffie-Helman Group 14.
The Firebox contains one default proposal, which appears in the IPSec Proposals list. This proposal specifies the ESP data protection method, AES 256-bit encryption, and SHA256 authentication. For this example, we use the default proposal. You can either:
- Use the default proposal.
- Remove the default proposal. Then select a different proposal in the drop-down list and click Add.
- Add an additional proposal, as described in Add a Phase 2 Proposal.
Click OK to return to the Branch Office IPSec Tunnel dialog box.
The tunnel you added appears on the Branch Office IPSec Tunnels list.

Screen shot of the Branch Office IPSec Tunnels dialog box with new tunnel added

Click Close and save the changes to the Firebox.

The Firebox at Site A is now configured.