IPv6 IPsec VPN

This chapter describes how to configure your FortiGate unit’s IPv6 IPsec VPN functionality.

l Overview of IPv6 IPsec support l Configuring IPv6 IPsec VPNs l Site-to-site IPv6 over IPv6 VPN example l Site-to-site IPv4 over IPv6 VPN example l Site-to-site IPv6 over IPv4 VPN example

Overview of IPv6 IPsec support

FortiOS supports route-based IPv6 IPsec, but not policy-based. This section describes how IPv6 IPsec support differs from IPv4 IPsec support.

Where both the gateways and the protected networks use IPv6 addresses, sometimes called IPv6 over IPv6, you can create either an auto-keyed or manually-keyed VPN. You can also combine IPv6 and IPv4 addressing in an auto-keyed VPN in the following ways:

IPv4 over IPv6	The VPN gateways have IPv6 addresses. The protected networks have IPv4 addresses. The phase 2 configurations at either end use IPv4 selectors.
IPv6 over IPv4	The VPN gateways have IPv4 addresses. The protected networks use IPv6 addresses. The phase 2 configurations at either end use IPv6 selectors.

Compared with IPv4 IPsec VPN functionality, there are some limitations:

l Except for IPv6 over IPv4, remote gateways with Dynamic DNS are not supported. l Selectors cannot be firewall address names. Only IP address, address range and subnet are supported. l Redundant IPv6 tunnels are not supported.

Certificates

On a VPN with IPv6 phase 1 configuration, you can authenticate using VPN certificates in which the common name (cn) is an IPv6 address. The cn-type keyword of the user peer command has an option, ipv6, to support this.

Configuring IPv6 IPsec VPNs

Configuration of an IPv6 IPsec VPN follows the same sequence as for an IPv4 route-based VPN: phase 1 settings, phase 2 settings, security policies, and routing.

Phase 1 configuration

In the web-based manager, you define the Phase 1 as IPv6 in the Advanced settings. Enable the IPv6 Version check box. You can then enter an IPv6 address for the remote gateway.

In the CLI, you define an IPsec phase 1 configuration as IPv6 by setting ip-version to 6. Its default value is 4. Then, the local-gw and remote-gw keywords are hidden and the corresponding local-gw6 and remotegw6 keywords are available. The values for local-gw6 and remote-gw6 must be IPv6 addresses. For example:

config vpn ipsec phase1-interface edit tunnel6 set ip-version 6

set remote-gw6 0:123:4567::1234 set interface port3 set proposal 3des-md5

end

Phase 2 configuration

To create an IPv6 IPsec phase 2 configuration in the web-based manager, you need to define IPv6 selectors in the Advanced settings. Change the default “0.0.0.0/0” address for Source address and Destination address to the IPv6 value “::/0”. If needed, enter specific IPv6 addresses, address ranges or subnet addresses in these fields.

In the CLI, set src-addr-type and dst-addr-type to ip6, range6 or subnet6 to specify IPv6 selectors. By default, zero selectors are entered, “::/0” for the subnet6 address type, for example. The simplest IPv6 phase 2 configuration looks like this:

config vpn ipsec phase2-interface edit tunnel6_p2 set phase1name tunnel6 set proposal 3des-md5 set src-addr-type subnet6 set dst-addr-type subnet6

end

Security policies

To complete the VPN configuration, you need a security policy in each direction to permit traffic between the protected network’s port and the IPsec interface. You need IPv6 policies unless the VPN is IPv4 over IPv6.

Routing

Appropriate routing is needed for both the IPsec packets and the encapsulated traffic within them. You need a route, which could be the default route, to the remote VPN gateway via the appropriate interface. You also need a route to the remote protected network via the IPsec interface.

To create a static route – web-based manager:

1. Go to Network > Static Routes.
2. Select the drop-down arrow on the Create New button and select IPv6 Route.
3. Enter the information and select OK.

To create a static route – CLI:

1. In the CLI, use the router static6 command. For example, where the remote network is fec0:0000:0000:0004::/64 and the IPsec interface is toB:

config router static6 edit 1 set device port2 set dst 0::/0

next edit 2 set device toB

set dst fec0:0000:0000:0004::/64

next

end

If the VPN is IPV4 over IPv6, the route to the remote protected network is an IPv4 route. If the VPN is IPv6 over IPv4, the route to the remote VPN gateway is an IPv4 route.

Site-to-site IPv6 over IPv6 VPN example

In this example, computers on IPv6-addressed private networks communicate securely over public IPv6 infrastructure.

Example IPv6-over-IPv6 VPN topology

Configure FortiGate A interfaces

Port 2 connects to the public network and port 3 connects to the local network.

config system interface edit port2 config ipv6 set ip6-address fec0::0001:209:0fff:fe83:25f2/64

end

next edit port3 config ipv6 set ip6-address fec0::0000:209:0fff:fe83:25f3/64

end

next

end

Configure FortiGate A IPsec settings

The phase 1 configuration creates a virtual IPsec interface on port 2 and sets the remote gateway to the public IP address FortiGate B. This configuration is the same as for an IPv4 route-based VPN, except that ip-version is set to 6 and the remote-gw6 keyword is used to specify an IPv6 remote gateway address.

config vpn ipsec phase1-interface edit toB set ip-version 6 set interface port2

set remote-gw6 fec0:0000:0000:0003:209:0fff:fe83:25c7 set dpd enable set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

By default, phase 2 selectors are set to accept all subnet addresses for source and destination. The default setting for src-addr-type and dst-addr-type is subnet. The IPv6 equivalent is subnet. The default subnet addresses are 0.0.0.0/0 for IPv4, ::/0 for IPv6.

config vpn ipsec phase2-interface edit toB2 set phase1name toB set proposal 3des-md5 3des-sha1 set pfs enable set replay enable set src-addr-type subnet6 set dst-addr-type subnet6

end

Configure FortiGate A security policies

Security policies are required to allow traffic between port3 and the IPsec interface toB in each direction. The address all6 must be defined using the firewall address6 command as ::/0.

config firewall policy6 edit 1 set srcintf port3 set dstintf toB set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

next edit 2 set srcintf toB set dstintf port3 set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

end

Configure FortiGate A routing

This simple example requires just two static routes. Traffic to the protected network behind FortiGate B is routed via the virtual IPsec interface toB. A default route sends all IPv6 traffic out on port2.

config router static6 edit 1 set device port2 set dst 0::/0

next edit 2 set device toB

set dst fec0:0000:0000:0004::/64 end

Configure FortiGate B

The configuration of FortiGate B is very similar to that of FortiGate A. A virtual IPsec interface toA is configured on port2 and its remote gateway is the public IP address of FortiGate A. Security policies enable traffic to pass between the private network and the IPsec interface. Routing ensures traffic for the private network behind FortiGate A goes through the VPN and that all IPv6 packets are routed to the public network.

config system interface edit port2 config ipv6 set ip6-address fec0::0003:209:0fff:fe83:25c7/64

end

next edit port3 config ipv6 set ip6-address fec0::0004:209:0fff:fe83:2569/64

end

end

config vpn ipsec phase1-interface edit toA set ip-version 6 set interface port2

set remote-gw6 fec0:0000:0000:0001:209:0fff:fe83:25f2 set dpd enable set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

config vpn ipsec phase2-interface edit toA2 set phase1name toA set proposal 3des-md5 3des-sha1 set pfs enable set replay enable set src-addr-type subnet6 set dst-addr-type subnet6

end

config firewall policy6 edit 1 set srcintf port3 set dstintf toA set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

next edit 2 set srcintf toA set dstintf port3 set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

end

config router static6 edit 1

set device port2 set dst 0::/0

next edit 2

set device toA

set dst fec0:0000:0000:0000::/64

end

Site-to-site IPv4 over IPv6 VPN example

In this example, two private networks with IPv4 addressing communicate securely over IPv6 infrastructure.

Example IPv4-over-IPv6 VPN topology

Configure FortiGate A interfaces

Port 2 connects to the IPv6 public network and port 3 connects to the IPv4 LAN.

config system interface edit port2 config ipv6 set ip6-address fec0::0001:209:0fff:fe83:25f2/64

end

next edit port3 set 192.168.2.1/24 end

Configure FortiGate A IPsec settings

The phase 1 configuration is the same as in the IPv6 over IPv6 example.

config vpn ipsec phase1-interface edit toB set ip-version 6 set interface port2

set remote-gw6 fec0:0000:0000:0003:209:0fff:fe83:25c7 set dpd enable set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

The phase 2 configuration is the same as you would use for an IPv4 VPN. By default, phase 2 selectors are set to accept all subnet addresses for source and destination.

config vpn ipsec phase2-interface edit toB2 set phase1name toB set proposal 3des-md5 3des-sha1 set pfs enable set replay enable

end

Configure FortiGate A security policies

Security policies are required to allow traffic between port3 and the IPsec interface toB in each direction. These are IPv4 security policies.

config firewall policy edit 1 set srcintf port3 set dstintf toB set srcaddr all set dstaddr all set action accept set service ANY set schedule always

next edit 2 set srcintf toB set dstintf port3 set srcaddr all set dstaddr all set action accept set service ANY set schedule always

end

Configure FortiGate A routing

This simple example requires just two static routes. Traffic to the protected network behind FortiGate B is routed via the virtual IPsec interface toB using an IPv4 static route. A default route sends all IPv6 traffic, including the IPv6 IPsec packets, out on port2.

config router static6 edit 1 set device port2

set dst 0::/0

next edit 2 set device toB set dst 192.168.3.0/24

end

Configure FortiGate B

The configuration of FortiGate B is very similar to that of FortiGate A. A virtual IPsec interface toA is configured on port2 and its remote gateway is the public IP address of FortiGate A. The IPsec phase 2 configuration has IPv4 selectors.

IPv4 security policies enable traffic to pass between the private network and the IPsec interface. An IPv4 static route ensures traffic for the private network behind FortiGate A goes through the VPN and an IPv6 static route ensures that all IPv6 packets are routed to the public network.

config system interface edit port2 config ipv6 set ip6-address fec0::0003:fe83:25c7/64

end

next edit port3 set 192.168.3.1/24

end

config vpn ipsec phase1-interface edit toA set ip-version 6 set interface port2

set remote-gw6 fec0:0000:0000:0001:209:0fff:fe83:25f2 set dpd enable set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

config vpn ipsec phase2-interface edit toA2 set phase1name toA set proposal 3des-md5 3des-sha1 set pfs enable set replay enable

end

config firewall policy edit 1 set srcintf port3 set dstintf toA set srcaddr all set dstaddr all set action accept set service ANY set schedule always

next edit 2 set srcintf toA set dstintf port3 set srcaddr all set dstaddr all

set action accept set service ANY set schedule always

end

config router static6 edit 1

set device port2 set dst 0::/0

next edit 2

set device toA set dst 192.168.2.0/24

end

Site-to-site IPv6 over IPv4 VPN example

In this example, IPv6-addressed private networks communicate securely over IPv4 public infrastructure.

Example IPv6-over-IPv4 VPN topology

Configure FortiGate A interfaces

Port 2 connects to the IPv4 public network and port 3 connects to the IPv6 LAN.

config system interface edit port2 set 10.0.0.1/24

next edit port3 config ipv6 set ip6-address fec0::0001:209:0fff:fe83:25f3/64

end

Configure FortiGate A IPsec settings

The phase 1 configuration uses IPv4 addressing.

config vpn ipsec phase1-interface edit toB set interface port2 set remote-gw 10.0.1.1 set dpd enable set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

The phase 2 configuration uses IPv6 selectors. By default, phase 2 selectors are set to accept all subnet addresses for source and destination. The default setting for src-addr-type and dst-addr-type is subnet. The IPv6 equivalent is subnet6. The default subnet addresses are 0.0.0.0/0 for IPv4, ::/0 for IPv6.

config vpn ipsec phase2-interface edit toB2 set phase1name toB set proposal 3des-md5 3des-sha1 set pfs enable set replay enable set src-addr-type subnet6 set dst-addr-type subnet6

end

Configure FortiGate A security policies

IPv6 security policies are required to allow traffic between port3 and the IPsec interface toB in each direction.

Define the address all6 using the firewall address6 command as ::/0.

config firewall policy6 edit 1 set srcintf port3 set dstintf toB set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

next edit 2 set srcintf toB set dstintf port3 set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always end

Configure FortiGate A routing

This simple example requires just two static routes. Traffic to the protected network behind FortiGate B is routed via the virtual IPsec interface toB using an IPv6 static route. A default route sends all IPv4 traffic, including the IPv4 IPsec packets, out on port2.

config router static6 edit 1 set device toB

set dst fec0:0000:0000:0004::/64

end

config router static edit 1 set device port2 set dst 0.0.0.0/0 set gateway 10.0.0.254 end

Configure FortiGate B

The configuration of FortiGate B is very similar to that of FortiGate A. A virtual IPsec interface toA is configured on port2 and its remote gateway is the IPv4 public IP address of FortiGate A. The IPsec phase 2 configuration has IPv6 selectors.

IPv6 security policies enable traffic to pass between the private network and the IPsec interface. An IPv6 static route ensures traffic for the private network behind FortiGate A goes through the VPN and an IPv4 static route ensures that all IPv4 packets are routed to the public network.

config system interface edit port2 set 10.0.1.1/24

next edit port3 config ipv6 set ip6-address fec0::0004:209:0fff:fe83:2569/64

end

config vpn ipsec phase1-interface edit toA set interface port2 set remote-gw 10.0.0.1 set dpd enable set psksecret maryhadalittlelamb set proposal 3des-md5 3des-sha1

end

config vpn ipsec phase2-interface edit toA2 set phase1name toA set proposal 3des-md5 3des-sha1 set pfs enable set replay enable set src-addr-type subnet6 set dst-addr-type subnet6

end

config firewall policy6 edit 1 set srcintf port3 set dstintf toA set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

next edit 2 set srcintf toA set dstintf port3 set srcaddr all6 set dstaddr all6 set action accept set service ANY set schedule always

end

config router static6 edit 1 set device toA

set dst fec0:0000:0000:0000::/64

end

config router static edit 1 set device port2 set gateway 10.0.1.254

end

TCP MSS values

TCP MSS values, which control the maximum amount of data that can be sent in a single packet, can be set for IPv6 policies (for both the sender and the receiver). You can configure TCP MSS values in IPv6 using the following CLI commands:

config firewall policy6 edit <index_int> set tcp-mss-sender <value> set tcp-mss-receiver <value>

end