IPsec VPN (5.6)

IPsec VPN (5.6)

New IPsec VPN features added to FortiOS 5.6.

Improvement to stats crypto command output (403995)

The CLI command get vpn ipsec stats crypto now has a better format for the information it shows in differentiating between NP6 lite and SOC3 (CP). To further avoid confusion, all engine’s encryption (encrypted/decrypted) and integrity (generated/validated) information is shown under the same heading, not separate headings.

Improved certificate key size control commands (397883)

Proxy will choose the same SSL key size as the HTTPS server. If the key size from the server is 512, the proxy will choose 1024. If the key size is bigger than 1024, the proxy will choose 2048.

As a result, the firewall ssl-ssh-profile commands certname-rsa, certname-dsa, and certname-ecdsa have been replaced with more specific key size control commands under vpn certificate setting.


CLI syntax

config vpn certificate setting set certname-rsa1024 <name> set certname-rsa2048 <name> set certname-dsa1024 <name> set certname-dsa2048 <name> set certname-ecdsa256 <name> set certname-ecdsa384 <name>


Support bit-based keys in IKE (397712)

As per FIPS-CC required standards, as well as RFC 4306, IKE supports pre-shared secrets to be entered as both ASCII string values and as hexadecimal encoded values. This feature parses hex encoded input (indicated by the leading characters 0x) and converts the input into binary data for storage.

With this change, the psksecret and psksecret-remote entries under the IPsec VPN CLI command config vpn ipsec-phase1-interface have been amended to differentiate user input as either ASCII string or hex encoded values.

IKEv2 asymmetric authentication (393073)

Support added for IKEv2 asymmetric authentication, allowing both sides of an authentication exchange to use different authentication methods, for example the initiator may be using a shared key, while the responder may have a public signature key and certificate.

A new command, authmethod-remote, has been added to config vpn ipsec phase1-interface.

For more detailed information on authentication of the IKE SA, see RFC 5996 Internet Key Exchange Protocol Version 2 (IKEv2).

Allow mode-cfg with childless IKEv2 (391567)

An issue that prevented childless-ike from being enabled at the same time as mode-cfg has been resolved. Both options can now be enabled at once under config vpn ipsec phase1-interface.

IKEv2 Digital Signature Authentication support (389001)

FortiOS supports the use of Digital Signature authentication, which changes the format of the Authentication Data payload in order to support different signature methods.

Instead of just containing a raw signature value calculated as defined in the original IKE RFCs, the Auth Data now includes an ASN.1 formatted object that provides details on how the signature was calculated, such as the signature type, hash algorithm, and signature padding method.

For more detailed information on IKEv2 Digital Signature authentication, see RFC 7427 Signature Authentication in the Internet Key Exchange Version 2 (IKEv2).

Passive static IPsec VPN (387913)

New commands have been added to config vpn ipsec phase1-interface to prevent initiating

VPN connection. Static IPsec VPNs can be configured in tunnel mode, without initiating tunnel negotiation or rekey.

To allow a finer configuration of the tunnel, the rekey option is removed from config system global and added to config vpn ipsec phase1-interface.

CLI syntax

config vpn ipsec phase1-interface edit <example> set rekey {enable | disable} set passive-mode {enable | disable} set passive-tunnel-interface {enable | disable}


Phase 2 wizard simplified (387725)

Previously, for a site-to-site VPN, phase 2 selectors had their static routes created in the IPsec VPN wizard by adding IP addresses in string format. Now, since addresses and address groups are already created for these addresses, the address group can be used in the route directly. This means that the route can be modified simply by modifying the address/groups that were created when the VPN was initially created.

With this change, the VPN wizard will create less objects internally, and reduce complexity.

In addition, a blackhole route route will be created by default with a higher distance-weight set than the default route. This is to prevent traffic from flowing out of another route if the VPN interface goes down. In these instances, the traffic will instead be silently discarded.

Unique IKE ID enforcement (383296)

All IPsec VPN peers now connect with unique IKE identifiers. To implement this, a new phase1 CLI command has been added (enforce-unique-id) which, when enabled, requires all IPsec VPN clients to use a unique identifier when connecting.

CLI syntax

config vpn ipsec phase1 edit <name> set enforce-unique-id {keep-new | keep-old | disable} Default is disable. next


Use keep-new to replace the old connection if an ID collision is detected on the gateway. Use keep-old to reject the new connection if an ID collision is detected.

FortiView VPN tunnel map feature (382767)

A geospatial map has been added to FortiView to help visualize IPsec and SSL VPN connections to a FortiGate using Google Maps. Adds geographical-IP API service for resolving spatial locations from IP addresses.


This feature can be found under FortiView > VPN.

Childless IKEv2 initiation (381650)

As documented in RFC 6023, when both sides support the feature, no child IPsec SA is brought up during the initial AUTH of the IKEv2 negotiation. Support for this mode is not actually negotiated, but the responder indicates support for it by including a CHILDLESS_IKEV2_SUPPORTED Notify in the initial SA_INIT reply. The initiator is then free to send its AUTH without any SA or TS payloads if it also supports this extension.

CLI syntax

config vpn ipsec phase1-interface edit ike set ike-version 2 set childless-ike enable

next end

Due to the way configuration payloads (IKEV2_PAYLOAD_CONFIG) are handled in the current code base, mode-cfg and childless-ike aren’t allowed to be enabled at the same time. Processing config payloads for mode-cfg requires a child ph2handle to be created, but with childless-ike we completely avoid creating the child ph2 in the first place which makes the two features incompatible. It may be possible to support both in the future, but a deeper rework of the config payload handling is required.

Allow peertype dialup for IKEv2 pre-shared key dynamic phase1 (378714)

Restored peertype dialup that was removed in a previous build (when IKEv2 PSK gateway re-validation was not yet supported).

If peertype is dialup, IKEv2 AUTH verify uses user password in the user group “usrgrp” of phase1. The “psksecret” in phase1 is ignored.

CLI syntax

config vpn ipsec phase1-interface edit “name” set type dynamic set interface “wan1” set ike-version 2 set peertype dialup set usrgrp “local-group”



IPsec default phase1/phase1-interface peertype changed from ‘any’ to ‘peer’ (376340)

Previously, when authmethod was changed to signature, peertype automatically changed to peer and required a peer to be set. This change was done to try to provide a more secure initial configuration, while allowing the admin to set peertype back to any if that’s what they really wanted. The default value was kept at any in the CLI. However, this caused problems with copy/pasting configurations and with FMG because if peertype any wasn’t explicitly provided, the CLI was switched to peertype peer.

This patch changes the default peertype to peer now; peertype any is considered non-default and will be printed out on any config listing. Upgrade code has been written to ensure that any older build that was implicitly using set peertype any has this setting preserved.

IPsec GUI bug fixes (374326)

Accept type “Any peer ID” is available when creating IPsec tunnel with authmethod, pre-shared key, ikev1 main mode/aggressive mode, and ikev2.

Support for IKEv2 Message Fragmentation (371241)

Added support for IKEv2 Message Fragmentation, as described in RFC 7383.

Previously, when sending and IKE packets with IKEv1, the whole packet is sent once, and it is only fragmented if there is a retransmission. With IKEv2, because RFC 7383 requires each fragment to be individually encrypted and authenticated, we would have to keep a copy of the unencrypted payloads around for each outgoing packet, in case the original single packet was never answered and we wanted to retry with fragments. So with this implementation, if the IKE payloads are greater than a configured threshold, the IKE packets are preemptively fragmented and encrypted.

CLI syntax

config vpn ipsec phase1-interface edit ike set ike-version 2 set fragmentation [enable|disable] set fragmentation-mtu [500-16000]



IPsec monitoring pages now based on phase 1 proposals not phase 2 (304246)

The IPsec monitor, found under Monitor > IPsec Monitor, was in some instances showing random uptimes even if the tunnel was in fact down.

Tunnels are considered as “up” if at least one phase 2 selector is active. To avoid confusion, when a tunnel is down, IPsec Monitor will keep the Phase 2 Selectors column, but hide it by default and be replaced with Phase 1 status column.


IPv6 (5.6)

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