Set Up an IPSec Tunnel
The IPSec tunnel configuration allows you to authenticate and/or encrypt the data (IP packet) as it traverses the tunnel.
If you are setting up the firewall to work with a peer that supports policy-based VPN, you must define Proxy IDs. Devices that support policy-based VPN use specific security rules/policies or access-lists (source addresses, destination addresses and ports) for permitting interesting traffic through an IPSec tunnel. These rules are referenced during quick mode/IKE phase 2 negotiation, and are exchanged as Proxy-IDs in the first or the second message of the process. So, if you are configuring the firewall to work with a policy-based VPN peer, for a successful phase 2 negotiation you must define the Proxy-ID so that the setting on both peers is identical. If the Proxy-ID is not configured, because the firewall supports route-based VPN, the default values used as Proxy-ID are source ip: 0.0.0.0/0, destination ip: 0.0.0.0/0 and application: any; and when these values are exchanged with the peer, it results in a failure to set up the VPN connection.
- Selectand thenNetworkIPSec TunnelsAdda new tunnel configuration.
- On theGeneraltab, enter aNamefor the tunnel.
- Select theTunnel interfaceon which to set up the IPSec tunnel.To create a new tunnel interface:
Use your trust zone as the termination point for the tunnel—Select the zone. Associating the tunnel interface with the same zone (and virtual router) as the external-facing interface on which the packets enter the firewall mitigates the need to create inter-zone routing.Or:Create a separate zone for VPN tunnel termination(Recommended)—SelectNew Zone, define aNamefor the new zone (for example vpn-corp), and clickOK.
- Select. (You can also selectTunnel InterfaceNew Tunnel Interfaceand clickNetworkInterfacesTunnelAdd.)
- In theInterface Namefield, specify a numeric suffix, such as.2.
- On theConfigtab, select theSecurity Zonelist to define the zone as follows:
- ForVirtual Router, selectdefault.
- (Optional) If you want to assign an IPv4 address to the tunnel interface, select theIPv4tab, andAddthe IP address and network mask, for example 10.31.32.1/32.
- (Optional) Enable IPv6 on the tunnel interface.
- Select the IPv6 tab on.NetworkInterfacesTunnelIPv6
- SelectEnable IPv6 on the interface.This option allows you to route IPv6 traffic over an IPv4 IPSec tunnel and will provide confidentiality between IPv6 networks. The IPv6 traffic is encapsulated by IPv4 and then ESP. To route IPv6 traffic to the tunnel, you can use a static route to the tunnel, or use OSPFv3, or use a Policy-Based Forwarding (PBF) rule.
- Enter the 64-bit extended uniqueInterface IDin hexadecimal format, for example, 00:26:08:FF:FE:DE:4E:29. By default, the firewall will use the EUI-64 generated from the physical interface’s MAC address.
- To assign an IPv6Addressto the tunnel interface,Addthe IPv6 address and prefix length, for example 2001:400:f00::1/64. If Prefix is not selected, the IPv6 address assigned to the interface will be wholly specified in the address text box.
- SelectUse interface ID as host portionto assign an IPv6 address to the interface that will use the interface ID as the host portion of the address.
- SelectAnycastto include routing through the nearest node.
- Set up key exchange.On theGeneraltab, configure one of the following types of key exchange:Set up Auto Key exchangeSet up Manual Key exchange
- Specify theLocal SPIfor the local firewall. SPI is a 32-bit hexadecimal index that is added to the header for IPSec tunneling to assist in differentiating between IPSec traffic flows; it is used to create the SA required for establishing a VPN tunnel.
- Select theInterfacethat will be the tunnel endpoint, and optionally select the IP address for the local interface that is the endpoint of the tunnel.
- Select the protocol to be used—AHorESP.
- For AH, select theAuthenticationmethod and enter aKeyand thenConfirm Key.
- For ESP, select theAuthenticationmethod and enter aKeyand thenConfirm Key. Then, select theEncryptionmethod and enter aKeyand thenConfirm Key, if needed.
- Specify theRemote SPIfor the remote peer.
- Enter theRemote Address, the IP address of the remote peer.
- Protect against a replay attack.Anti-replay is a sub-protocol of IPSec and is part of the Internet Engineering Task Force (IETF) Request for Comments (RFC) 6479. The anti-replay protocol is used to prevent hackers from injecting or making changes in packets that travel from a source to a destination and uses a unidirectional security association in order to establish a secure connection between two nodes in the network.After a secure connection is established, the anti-replay protocol uses packet sequence numbers to defeat replay attacks. When the source sends a message, it adds a sequence number to its packet; the sequence number starts at 0 and is incremented by 1 for each subsequent packet. The destination maintains the sequence of numbers in asliding windowformat, maintains a record of the sequence numbers of validated received packets, and rejects all packets that have a sequence number that is lower than the lowest in the sliding window (packets that are too old) or packets that already appear in the sliding window (duplicate or replayed packets). Accepted packets, after they are validated, update the sliding window, displacing the lowest sequence number out of the window if it was already full.
- On the General tab, selectShow Advanced Optionsand selectEnable Replay Protectionto detect and neutralize against replay attacks.
- Select theAnti Replay Windowto use. You can select a anti-replay window size of 64, 128, 256, 512, 1024, 2048, or 4096. The default is 1024.
- (Optional) Preserve the Type of Service header for the priority or treatment of IP packets.In the Show Advanced Options section, selectCopy TOS Header. This copies the Type of Service (TOS) header from the inner IP header to the outer IP header of the encapsulated packets in order to preserve the original TOS information.If there are multiple sessions inside the tunnel (each with a different TOS value), copying the TOS header can cause the IPSec packets to arrive out of order.
- (Optional) SelectAdd GRE Encapsulationto enable GRE over IPSec.Add GRE encapsulation in cases where the remote endpoint requires traffic to be encapsulated within a GRE tunnel before IPSec encrypts the traffic. For example, some implementations require multicast traffic to be encapsulated before IPSec encrypts it. Add GRE Encapsulation when the GRE packet encapsulated in IPSec has the same source IP address and destination IP address as the encapsulating IPSec tunnel.
- Enable Tunnel Monitoring.You must assign an IP address to the tunnel interface for monitoring.To alert the device administrator to tunnel failures and to provide automatic failover to another tunnel interface:
- SelectTunnel Monitor.
- Specify aDestination IPaddress on the other side of the tunnel to determine if the tunnel is working properly.
- Select aProfileto determine the action upon tunnel failure. To create a new profile, see Define a Tunnel Monitoring Profile.
- Create a Proxy ID to identify the VPN peers.This step is required only if the VPN peer uses policy-based VPN.
- Selectand clickNetworkIPSec TunnelsAdd.
- Select theProxy IDstab.
- Select theIPv4orIPv6tab.
- ClickAddand enter theProxy IDname.
- Enter theLocalIP address or subnet for the VPN gateway.
- Enter theRemoteaddress for the VPN gateway.
- Select theProtocol:
- Number—Specify the protocol number (used for interoperability with third-party devices).
- Any—Allows TCP and/or UDP traffic.
- TCP—Specify the Local Port and Remote Port numbers.
- UDP—Specify the Local Port and Remote Port numbers.
- Commit your changes.ClickOKandCommit.
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