Implementing Network Admission Control Phase One Configuration and Deployment
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Table Of Contents

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Acronyms

Definitions

Related Documentation

Configuring Network Admission Control

CTA Documentation


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This appendix provides a list of acronyms and definitions of terms used in Network Admission Control (NAC). It provides sources of further information about NAC and includes the following sections:

Acronyms

Definitions

Related Documentation

Acronyms

Table B-1 Acronyms 

Acronyms
Definition

AAA

Authentication, Authorization, and Accounting

ACE

Access Control Element

ACL

Access Control List

Cisco Secure ACS

Access Control Server

APT

Application Posture Token

AV

Anti Virus

AVP

Attribute Value Pair

CA

Certificate Authority

CTA

Cisco Trust Agent

EAP

Extensible Authentication Protocol

FW

Firewall

HCAP

Host Credential Authorization Protocol

HTTPS

Secure Hyper Text Transfer Protocol

IDS

Intrusion Detection Systems

NAC

Network Admission Control

NAD

Network Access Device

PA

Posture Agent

PB

Posture Broker

PEAP

Protected Extensible Authentication Protocol

RADIUS

Remote Access Dial In User Service

SPT

System Posture Token

TACS+

Terminal Access Controller Access Control System Plus

TLS

Transport Layer Security

TLV

Type Length Value

UDP

User Datagram Protocol

VPN

Virtual Private Network


Definitions

Table B-2 Definitions 

Term
Definition

AAA Server

Evaluates credentials from peer and determines network access policy for enforcement by Authenticator. May use back-end servers for credential evaluation, such as vendor-specific posture servers such as the NAI AV Server. Also supports access policies for "clientless hosts".

Access Accept

AAA Server returns Access Accept to Authenticator to indicate that the peer has had its credentials evaluated successfully and (optionally) that a new access policy is to be enforced as a result. Successful evaluation means that the Authenticator must keep state that the Peer has had its credentials checked so that the Peer is not checked again until it is time to re-validate the Peer.

Access Reject

AAA Server returns Access Reject to indicate that the credentials have not been evaluated successfully, and no (new) access is to be provided to the peer. Unsuccessful evaluation means that the Authenticator does not maintain state about the peer; that is, the peer credentials need to be checked again after some configurable hold period. The default access policy continues to apply to rejected peers.

Accounting

The process of collecting quantitative data about sessions for the purposes of troubleshooting, capacity planning, or auditing.

Association

A single instance of the L3 access control protocol (Apocope) between peer and authenticator. Represented by state of conversation, IP address of other party, active timers, keys used in status query.

Authentication

In the case of identity, the use of credentials to establish that a principal is who he or she claims to be. In the case of posture, the use of credentials to establish that the posture of the end-system is what the principal says it is.

Authenticator

Logical entity in the gateway that initiates the exchange of EAP credentials, relays EAP credential requests and responses between peer and AAA server, and enforces network access policy on a particular port or interface based on the results from the AAA server. Same functionality as authenticator in EAP or 802.1X, but does not include any AAA server functionality. In addition to acting as an EAP "pass-through" for EAP methods that require a AAA server, the authenticator implements EAP methods that do not require AAA server functionality, in particular, the EAP status query method.

Authorization

The act of determining what part of the network a principal is permitted to access based on identity or posture or both.

Cisco Trust Agent

Cisco software that implements peer functionality

Clientless host

A TCP/IP host that does not have the posture agent installed

Credential

A piece of information presented by a principal in support of a claim of identity or posture. Includes identity and posture information itself. Examples include username, password, and AV signature file version.

Default Access Policy

Access policy applied to a peer when the policy has not been updated as a result of an Access Accept

End-system

A TCP/IP host; for example, desktop, server, IP phone, printer

Gateway

L3 network device that has authenticator functionality. May be one or more hops from peer

Identity

A unique name associated with a principal.

IP Intercept ACL

A special type of access control list (ACL) that indicates which packets on an interface trigger validation of the peer (source IP address of the packet)

Network Access Device

First hop network device (as measured from peer) that has authenticator functionality

Network Access Filtering

A method of changing the downloadable access list depending on which network access device is receiving the download.

Network Device

L2 or L3 networking equipment such as switches, routers, wireless access points, and VPN concentrators

Peer

Logical entity in end-system that responds to requests for credentials from authenticator for the purposes of gaining access to restricted network. Referred to as supplicant in 802.1x. Same as peer in EAP.

Posture

The state of a device; for example, set of applications loaded on desktop; AV scan engine version and signature file version; FW version and rules file

Posture Agent

The software implementing the posturing process on a client machine. This includes, but is not limited to, the Cisco Trust Agent.

Posture Client

Cisco or third-party software that resides on the peer and responds to requests from posture agent for posture credentials.

Posture Server

Cisco or third-party back-end server that responds to requests from AAA server to validate vendor-specific posture credentials from posture client.

Principal

Something with an identity; for example, a user or a device.

Provisioning

Configuration of network devices and servers needed to deliver services for a principal.

User

A human being using a device.


Related Documentation

This section provides URLs to websites where you can obtain additional information about NAC. It includes the following topics:

Configuring Network Admission Control

CTA Documentation

Configuring Network Admission Control

Implementing Authentication Proxy— http://www.cisco.com/en/US/products/sw/secursw/ps1018/products_tech_note09186a0080094eb0.shtml

Configuring Authentication Proxy— http://www.cisco.com/en/US/docs/ios/12_1/security/configuration/guide/scdauthp.html

Cisco Secure ACS 3.3— http://www.cisco.com/univercd/cc/td/doc/product/access/acs_soft/csacs4nt/

CTA Documentation

CiscoWorks SIMS— http://www.cisco.com/univercd/cc/td/doc/product/rtrmgmt/cw2000/cw2000_b/sims/3_1_1/

Cisco Security Agent— http://www.cisco.com/univercd/cc/td/doc/product/vpn/ciscosec/csa/40/index.htm