To set up a VPN tunnel, the VPN peers or gateways must authenticate each other using preshared keys or digital certificates and establish a secure channel in which to negotiate the IPSec security association (SA) that will be used to secure traffic between the hosts on each side.
Set Up an IKE Gateway
Define the IKE Gateway. Select Network > Network Profiles > IKE Gateways, click Add, and on the General tab, enter the Name of the gateway. For Version, select IKEv1 only mode, IKEv2 only mode, or IKEv2 preferred mode. The IKE gateway begins its negotiation with its peer in the mode specified here. If you select IKEv2 preferred mode, the two peers will use IKEv2 if the remote peer supports it; otherwise they will use IKEv1. (The Version selection also determines which options are available on the Advanced Options tab.)
Establish the local endpoint of the tunnel (gateway). For Address Type, click IPv4 or IPv6. Select the physical, outgoing Interface on the firewall where the local gateway resides. From the Local IP Address drop-down, select the IP address that will be used as the endpoint for the VPN connection. This is the external-facing interface with a publicly routable IP address on the firewall.
Establish the peer at the far end of the tunnel (gateway). Select the Peer IP Type to be a Static or Dynamic address assignment. If the Peer IP Address is static, enter the IP address of the peer.
Specify how the peer is authenticated. Select the Authentication method: Pre-Shared Key or Certificate. If you choose Pre-Shared Key, proceed to the next step. If you choose Certificate, skip to Configure certificate-based authentication.
Configure a pre-shared key. Enter a Pre-shared Key, which is the security key to use for authentication across the tunnel. Re-enter the value to Confirm Pre-shared Key. Use a maximum of 255 ASCII or non-ASCII characters. Generate a key that is difficult to crack with dictionary attacks; use a pre-shared key generator, if necessary. For Local Identification, choose from the following types and enter a value that you determine: FQDN (hostname), IP address, KEYID (binary format ID string in HEX), User FQDN (email address). Local identification defines the format and identification of the local gateway. If no value is specified, the local IP address will be used as the local identification value. For Peer Identification, choose from the following types and enter the value: FQDN (hostname), IP address, KEYID (binary format ID string in HEX), User FQDN (email address). Peer identification defines the format and identification of the peer gateway. If no value is specified, the peer IP address will be used as the peer identification value. Proceed to Step 7 and continue from there.
Configure certificate-based authentication. Perform the remaining steps in this procedure if you selected Certificate as the method of authenticating the peer gateway at the opposite end of the tunnel. Select a Local Certificate that is already on the firewall from the drop-down, or Import a certificate, or Generate to create a new certificate. If you want to Import a certificate, Import a Certificate for IKEv2 Gateway Authentication and then return to this task. If you want to Generate a new certificate, Generate a Certificate and then return to this task. Click the HTTP Certificate Exchange check box if you want to configure Hash and URL (IKEv2 only). For an HTTP certificate exchange, enter the Certificate URL. For more information, see Hash and URL Certificate Exchange. Select the Local Identification type from the following: Distinguished Name (Subject), FQDN (hostname), IP address, User FQDN (email address), and enter the value. Local identification defines the format and identification of the local gateway. Select the Peer Identification type from the following: Distinguished Name (Subject), FQDN (hostname), IP address, User FQDN (email address), and enter the value. Peer identification defines the format and identification of the peer gateway. Select one type of Peer ID Check: Exact —Check this to ensure that the local setting and peer IKE ID payload match exactly. Wildcard —Check this to allow the peer identification to match as long as every character before the wildcard (*) matches. The characters after the wildcard need not match. Click Permit peer identification and certificate payload identification mismatch if you want to allow a successful IKE SA even when the peer identification does not match the peer identification in the certificate. Choose a Certificate Profile from the drop-down. A certificate profile contains information about how to authenticate the peer gateway. Click Enable strict validation of peer’s extended key use if you want to strictly control how the key can be used.
Configure advanced options for the gateway. Select the Advanced Options tab. In the Common Options section, Enable Passive Mode if you want the firewall to only respond to IKE connection requests and never initiate them. Enable NAT Traversal if you have a device performing NAT between the gateways, to have UDP encapsulation used on IKE and UDP protocols, enabling them to pass through intermediate NAT devices. If you chose IKEv1 only mode earlier, on the IKEv1 tab: Choose auto, aggressive, or main for the Exchange Mode. When a device is set to use auto exchange mode, it can accept both main mode and aggressive mode negotiation requests; however, whenever possible, it initiates negotiation and allows exchanges in main mode. If the exchange mode is not set to auto, you must configure both peers with the same exchange mode to allow each peer to accept negotiation requests. Select an existing profile or keep the default profile from IKE Crypto Profile drop-down. For details on defining an IKE Crypto profile, see Define IKE Crypto Profiles. (Only if using certificate-based authentication and the exchange mode is not set to aggressive mode) Click Enable Fragmentation to enable the firewall to operate with IKE Fragmentation. Click Dead Peer Detection and enter an Interval (range is 2-100 seconds). For Retry, define the time to delay (range is 2-100 seconds) before attempting to re-check availability. Dead peer detection identifies inactive or unavailable IKE peers by sending an IKE phase 1 notification payload to the peer and waiting for an acknowledgment. If you chose IKEv2 only mode or IKEv2 preferred mode in Step 1, on the IKEv2 tab: Select an IKE Crypto Profile from the drop-down, which configures IKE Phase 1 options such as the DH group, hash algorithm, and ESP authentication. For information about IKE crypto profiles, see IKE Phase 1. Enable Strict Cookie Validation if you want to always enforce cookie validation on IKEv2 SAs for this gateway. See Cookie Activation Threshold and Strict Cookie Validation. Enable Liveness Check and enter an Interval (sec) (default is 5) if you want to have the gateway send a message request to its gateway peer, requesting a response. If necessary, the Initiator attempts the liveness check up to 10 times. If it doesn’t get a response, the Initiator closes and deletes the IKE_SA and CHILD_SA. The Initiator will start over by sending out another IKE_SA_INIT.
Save the changes. Click OK and Commit.
Export a Certificate for a Peer to Access Using Hash and URL
IKEv2 supports Hash and URL Certificate Exchange as a method of having the peer at the remote end of the tunnel fetch the certificate from a server where you have exported the certificate. Perform this task to export your certificate to that server. You must have already created a certificate using Device > Certificate Management.
Export a Certificate for Hash and URL
Select Device > Certificates, and if your platform supports multiple virtual systems, for Location, select the appropriate virtual system. On the Device Certificates tab, select the certificate to Export to the server. The status of the certificate should be valid, not expired. The firewall will not stop you from exporting an invalid certificate. For File Format, select Binary Encoded Certificate (DER). Leave Export private key clear. Exporting the private key is unnecessary for Hash and URL. Click OK.
Import a Certificate for IKEv2 Gateway Authentication
Perform this task if you are authenticating a peer for an IKEv2 gateway and you did not use a local certificate already on the firewall; you want to import a certificate from elsewhere.
This task presumes that you selected Network > IKE Gateways, added a gateway, and for Local Certificate, you clicked Import.
Import a Certificate for IKEv2 Gateway Authentication
Import a certificate. Select Network > IKE Gateways, Add a gateway, and on the General tab, for Authentication, select Certificate. For Local Certificate, click Import. In the Import Certificate window, enter a Certificate Name for the certificate you are importing. Select Shared if this certificate is to be shared among multiple virtual systems. For Certificate File, Browse to the certificate file. Click on the file name and click Open, which populates the Certificate File field. For File Format, select one of the following: Base64 Encoded Certificate (PEM) —Contains the certificate, but not the key. It is cleartext. Encrypted Private Key and Certificate (PKCS12) —Contains both the certificate and the key. Select Import private key if the key is in a different file from the certificate file. The key is optional, with the following exception: You must import a key if you set the File Format to PEM. Enter a Key file by clicking Browse and navigating to the key file to import. Enter a Passphrase and Confirm Passphrase. Click OK.
Configure certificate-based authentication.
Change the Key Lifetime or Authentication Interval for IKEv2
This task is optional; the default setting of the IKEv2 IKE SA re-key lifetime is 8 hours. The default setting of the IKEv2 Authentication Multiple is 0, meaning the re-authentication feature is disabled. For more information, see SA Key Lifetime and Re-Authentication Interval.
To change the default values, perform the following task. A prerequisite is that an IKE crypto profile already exists.
Change the SA Key Lifetime or Authentication Interval
Change the SA key lifetime or authentication interval for an IKE Crypto profile. Select Network > Network Profiles > IKE Crypto and select the IKE Crypto profile that applies to the local gateway. For the Key Lifetime, select a unit ( Seconds, Minutes, Hours, or Days) and enter a value. The minimum is three minutes. For IKE Authentication Multiple, enter a value, which is multiplied by the lifetime to determine the re-authentication interval.
Save the configuration. Click OK and Commit.
Change the Cookie Activation Threshold for IKEv2
Perform the following task if you want a firewall to have a threshold different from the default setting of 500 half-opened SA sessions before cookie validation is required. For more information about cookie validation, see Cookie Activation Threshold and Strict Cookie Validation.
Change the Cookie Activation Threshold
Change the Cookie Activation Threshold. Select Device > Setup > Session and edit the VPN Session Settings. For Cookie Activation Threshold, enter the maximum number of half-opened SAs that are allowed before the responder requests a cookie from the initiator (range is 0-65535; default is 500). Click OK.
Save the configuration Click OK and Commit.
Configure IKEv2 Traffic Selectors
In IKEv2, you can configure Traffic Selectors, which are components of network traffic that are used during IKE negotiation. Traffic selectors are used during the CHILD_SA (tunnel creation) Phase 2 to set up the tunnel and to determine what traffic is allowed through the tunnel. The two IKE gateway peers must negotiate and agree on their traffic selectors; otherwise, one side narrows its address range to reach agreement. One IKE connection can have multiple tunnels; for example, you can assign different tunnels to each department to isolate their traffic. Separation of traffic also allows features such as QoS to be implemented. Use the following workflow to configure traffic selectors.
Configure Traffic Selectors for IKEv2
Select Network > IPSec Tunnels > Proxy IDs.
Select the IPv4 or IPv6 tab.
Click Add and enter the Name in the Proxy ID field.
In the Local field, enter the Source IP Address.
In the Remote field, enter the Destination IP Address.
In the Protocol field, select the transport protocol ( TCP or UDP) from the drop-down.
Click OK.

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