Cisco 500 Series, Configuration Manual

Page: 620 / 1140

30-4
Cisco Security Appliance Command Line Configuration Guide
OL-12172-03
Chapter 30 Configuring Connection Profiles, Group Policies, and Users
Connection Profiles
IPSec Tunnel-Group Connection Parameters
IPSec parameters include the following:
•
A client authentication method: preshared keys, certificates, or both.
– For IKE connections based on preshared keys, this is the alphanumeric key itself (up to 128
characters long), associated with the connection policy.
–
Peer-ID validation requirement—This parameter specifies whether to require validating the
identity of the peer using the peer’s certificate.
• An extended hybrid authentication method: XAUTH and hybrid XAUTH.
You use isakmp ikev1-user-authentication command to implement hybrid XAUTH authentication
when you need to use digital certificates for security appliance authentication and a different, legacy
method for remote VPN user authentication, such as RADIUS, or SecurID.
• ISAKMP (IKE) keepalive settings. This feature lets the security appliance monitor the continued
presence of a remote peer and report its own presence to that peer. If the peer becomes unresponsive,
the security appliance removes the connection. Enabling IKE keepalives prevents hung connections
when the IKE peer loses connectivity.
There are various forms of IKE keepalives. For this feature to work, both the security appliance and
its remote peer must support a common form. This feature works with the following peers:
– Cisco AnyConnect VPN Client
–
Cisco VPN Client (Release 3.0 and above)
– Cisco VPN 3000 Client (Release 2.x)
–
Cisco VPN 3002 Hardware Client
– Cisco VPN 3000 Series Concentrators
–
Cisco IOS software
– Cisco Secure PIX Firewall
Non-Cisco VPN clients do not support IKE keepalives.
If you are configuring a group of mixed peers, and some of those peers support IKE keepalives and
others do not, enable IKE keepalives for the entire group. The feature does not affect the peers that
do not support it.
If you disable IKE keepalives, connections with unresponsive peers remain active until they time
out, so we recommend that you keep your idle timeout short.
To change your idle timeout, see
“Configuring Group Policies” section on page 30-36 .
Note
To reduce connectivity costs, disable IKE keepalives if this group includes any clients
connecting via ISDN lines. ISDN connections normally disconnect if idle, but the IKE keepalive
mechanism prevents connections from idling and therefore from disconnecting.
If you do disable IKE keepalives, the client disconnects only when either its IKE or IPSec keys
expire. Failed traffic does not disconnect the tunnel with the Peer Timeout Profile values as it
does when IKE keepalives are enabled.