16.3.2. IPSec options

Global parameters that apply to every IPSec VPN connection of the PNS host can be set on the Global options tab.

Set special options of a particular IPSec VPN connection on the Connections tab and the Options and Keying submenu tabs.

Besides the Dead Peer detection parameters, as introduced in Section 16.3, Configuring IPSec connections, there are additional parameters that can be configured Under the Options tab.

Configuring 'Common options' parameters at IPSec Options tab

Figure 16.11. Configuring 'Common options' parameters at IPSec Options tab

Common options

  • Use IPComp compression

    If this parameter is enabled, that is the parameter is checked in, the daemon accepts compressed and uncompressed data as well. If the parameter is not enabled, that is, the parameter is not checked in, the daemon accepts only uncompressed data.

  • Exchange method

    The available values are: ikev1, ikev2.

    The key exchange method can be selected here for initializing the connection, that is ikev1 or ikev2.

  • Close action

    The available values are: none, clear, hold and restart.

    This parameter defines the action to take if the remote peer unexpectedly closes. This parameter is not supported for ikev1 connections.

  • Fragmentation

    The available values are: yes, accept, force and no.

    This parameter enables Internet Key Excahnge (IKE) fragmentation. Note that fragmented messages arriving from a peer are always processed, regardless of this parameter option.

    If this parameter is set to yes, that is, checked in, and the peer supports it, any oversized IKE message will be fragmented.

    If the parameter is set to accept fragmented content is supported arriving from the peer, yet the daemon does not send fragmented messages.

    If the parameter is set to force the initial IKE message will be fragmented.

  • Additional options

    This parameter enables the user to provide any additional StrongSwan parameter manually that is not available in the GUI. Also, if the configuration of a parameter is available though in the GUI, but the required setting is not, it can be manually defined here. Even already defined parameter configuration settings can be overwritten at Additional options, as the configuration will use the latest definition of the parameter. The parameters have to be provided in the format described on the StrongSwan documentation site, available at:

    https://wiki.strongswan.org/projects/strongswan/wiki/ConnSection.

The Keying parameters section of the Options tab specifies key-handling and key-exchange parameters. Modify these parameters only if it is necessary for compatibility with the remote endpoint.

Configuring keying parameters at IPSec Options tab

Figure 16.12. Configuring keying parameters at IPSec Options tab

Note

Do not modify these options unless it is required and it is perfectly clear how these parameter settings affect the configuration.

The options of the Keying tab specify the encryption used in the connection.

Keying parameters

  • Key life

    This parameter defines how long the key connection shall last, from the negotiation until expiry.

  • Key tries

    This parameter defines the number of attempts for negotiating or renegotiating the connection.

  • IKE lifetime

    This parameter defines the length of the keying channel connection before it is renegotiated.

  • Rekey

    Enabling this parameter requires the connection to be renegotiated when it is about to expire.

    Disabling this parameter will result in the daemon not requesting renegotiation, nevertheless, it does not prevent from responding to renegotiation requested from the other end.