Table Of Contents
Ability to Disable Extended Authentication for Static IPSec Peers
Supported Standards, MIBs, and RFCs
Disabling Xauth for Static IPSec Peers
Verifying Disabled Xauth for Static IPSec Peers
Disabling Xauth for Static IPSec Peers Configuration
Ability to Disable Extended Authentication for Static IPSec Peers
Feature History
This feature module describes the Ability to Disable Extended Authentication for Static IPSec Peers feature in Cisco IOS Release 12.2(4)T. It includes the following sections:
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Supported Standards, MIBs, and RFCs
Feature Overview
The Ability to Disable Extended Authentication for Static IPSec Peers feature allows users to disable extended authentication (Xauth), preventing the routers from being prompted for Xauth information—username and password.
Without the ability to disable Xauth, a user cannot select which peer on the same crypto map should use Xauth. That is, if a user has router-to-router IP security (IPSec) on the same crypto map as a virtual private network (VPN)-client-to-Cisco-IOS IPSec, both peers are prompted for a username and password. In addition, a remote static peer (a Cisco IOS router) cannot establish an Internet Key Exchange (IKE) security association (SA) with the local Cisco IOS router. (Xauth is not an optional exchange, so if a peer does not respond to an Xauth request, the IKE SA is deleted.) Thus, the same interface cannot be used to terminate IPSec to VPN clients (that need Xauth) as well as other Cisco IOS routers (that cannot respond to Xauth) unless this feature is implemented.
Benefits
If VPN-client-to-Cisco-IOS IPSec and router-to-router IPSec exist on a single interface, the Ability to Disable Extended Authentication for Static IPSec Peers feature allows a user to disable Xauth while configuring the preshared key for router-to-router IPSec. Thus, the router will not prompt the peer for a username and password, which are transmitted when Xauth occurs for VPN-client-to-Cisco-IOS IPSec.
Restrictions
Xauth can be disabled only if preshared keys are used as the authentication mechanism for the given crypto map.
Related Documents
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Supported Platforms
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Platform Support Through Feature Navigator
Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Feature Navigator. Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.
Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image.
To access Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions at http://www.cisco.com/register.
Feature Navigator is updated when major Cisco IOS software releases and technology releases occur. As of May 2001, Feature Navigator supports M, T, E, S, and ST releases. You can access Feature Navigator at the following URL:
http://www.cisco.com/go/fn
Supported Standards, MIBs, and RFCs
Standards
None
MIBs
None
To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:
http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
RFCs
No new or modified RFCs are supported by this feature.
Prerequisites
Before you can disable Xauth for static IPSec peers, you must complete the following tasks:
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For information on completing this task, refer to the AAA chapters of the Cisco IOS Security Configuration Guide, Release 12.2.
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For information on completing this task, refer to the section "Defining Transform Sets" in the chapter "Configuring IPSec Network Security" of the Cisco IOS Security Configuration Guide, Release 12.2.
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For information on completing this task, refer to the section "Creating Crypto Map Entries" in the chapter "Configuring IPSec Network Security" of the Cisco IOS Security Configuration Guide, Release 12.2.
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For information on completing this task, refer to the section "Creating Policies" in the chapter "Configuring Internet Key Exchange Security Protocol" of the Cisco IOS Security Configuration Guide, Release 12.2.
Configuration Tasks
See the following sections for configuration tasks for the Ability to Disable Extended Authentication for Static IPSec Peers feature. Each task in the list is identified as either required or optional.
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Disabling Xauth for Static IPSec Peers
To disable Xauth for router-to-router IPSec, use the following command in global configuration mode:
Verifying Disabled Xauth for Static IPSec Peers
To verify your configuration, use the show running-config command in EXEC mode.
Configuration Examples
This section provides the following configuration example:
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Disabling Xauth for Static IPSec Peers Configuration
The following example shows how the local peer specifies the preshared key, designates the remote peer by its IP address, and disables Xauth:
crypto isakmp key sharedkeystring address 172.21.230.33 no-xauth
Command Reference
This section documents the modified command. All other commands used with this feature are documented in the Cisco IOS Release 12.2 command reference publications.
crypto isakmp key
To configure a preshared authentication key, use the crypto isakmp key command in global configuration mode. You must configure this key whenever you specify preshared keys in an Internet Key Exchange (IKE) policy. To delete a preshared authentication key, use the no form of this command.
crypto isakmp key keystring address peer-address [mask] [no-xauth]
no crypto isakmp key keystring address peer-address
Syntax Description
Defaults
There is no default preshared authentication key.
Command Modes
Global configuration
Command History
11.3 T
This command was introduced.
12.1(1)T
The mask argument was added.
12.2(4)T
The no-xauth keyword was added.
Usage Guidelines
Use this command to configure preshared authentication keys. You must perform this command at both peers.
If an IKE policy includes preshared keys as the authentication method, these preshared keys must be configured at both peers—otherwise the policy cannot be used (the policy will not be submitted for matching by the IKE process). The crypto isakmp key command is the second task required to configure the preshared keys at the peers. (The first task is accomplished with the crypto isakmp identity command.)
Use the address keyword if the remote peer ISAKMP identity was set with its IP address.
With the address keyword, you can also use the mask argument to indicate the remote peer ISAKMP identity will be established using the preshared key only. If the mask argument is used, preshared keys are no longer restricted between two users.
Note
Preshared keys no longer work when hostname is sent as the identity; thus, hostname as the identity in preshared key authentication is no longer supported. According to the way preshared key authentication is designed in IKE main mode, the preshared keys must be based on the IP address of the peers. Although a user can still send the hostname as identity in preshared key authentication, the key is searched on the IP address of the peer; if the key is not found (based on the IP address), the negotiation will fail.
If crypto isakmp identity hostname is configured as identity, the preshared key must be configured with the peer's IP address for the process to work.
Use the no-xauth keyword to prevent the router from prompting the peer for Xauth information (username and password). This keyword disables Xauth for static IPSec peers. no-xauth should be enabled when configuring the preshared key for router-to-router IPSec—not VPN-client-to-Cisco-IOS IPSec.
Examples
In the following example, the remote peer "RemoteRouter" specifies an ISAKMP identity by address:
crypto isakmp identity addressNow, the preshared key must be specified at each peer.
In the following example, the local peer specifies the preshared key and designates the remote peer by its IP address and a mask:
crypto isakmp key sharedkeystring address 172.21.230.33 255.255.255.255Related Commands
Guest
