Home > Articles > Cisco Certification > CCIE > CCIE Self-Study: Security Protocols

CCIE Self-Study: Security Protocols

  • Sample Chapter is provided courtesy of Cisco Press.
  • Date: Oct 28, 2005.

Chapter Description

This chapter covers some of today's most widely used technologies that enable network administrators to ensure that sensitive data is secure from unauthorized sources. Standards such as IP Security (IPSec) and encryption standards are covered, as are all the fundamental foundation topics you need to understand to master the topics covered in the CCIE Security written exam.

Extensible Authentication Protocol, Protected EAP, and Temporal Key Integrity Protocol

Extensible Authentication Protocol (EAP) enables the dynamic selection of the authentication mechanism at authentication time based on information transmitted in the Access-Request (that is, via RADIUS). PPP also supports EAP during the link establishment phase.

EAP allows the authenticator to request more information before determining the specific authentication mechanism.

A proposal jointly submitted to the IEEE by Cisco Systems, Microsoft, and various other organizations introduced Protected EAP (PEAP), an EAP to provide enhanced functionality and security features to wireless networks. PEAP is today's preferred authentication mechanism in wireless networks.

PEAP provides the following security benefits:

  • Relies on Transport Layer Security (TLS) to allow nonencrypted authentication types such as EAP-Generic Token Card (GTC) and One Time Password (OTP) support.
  • Uses server-side PKI-based digital certification authentication.
  • Allows authentication to an extended suite of directories, including Lightweight Directory Access Protocol (LDAP), Novell NDS, and OTP databases.
  • Uses TLS to encrypt all user-sensitive authentication information.
  • Supports password change at expiration.
  • Does not expose the logon username in the EAP identity response.
  • Is not vulnerable to dictionary attacks.

That functionality is provided to wireless client adapters, which may support different authentication types, to communicate with different back-end servers such as RADIUS servers. EAP can be used with wired networks as well.

Microsoft Windows XP supports an extension to EAP, namely Extensible Authentication Protocol Transport Layer Security (EAP-TLS). Hence, a number of options are available to end users so that authentication may be completed securely over a wireless network. Recently Microsoft has added support for EAP-TLS and PEAP to several of its operating systems.

Figure 4-17 displays a typical wireless network in which a user labeled PEAP Client is required to authenticate to either a Cisco Secure ACS or the Cisco Access Registrar. The Cisco Access Registrar is based on a client/server model, which supports AAA. The client passes user information on to the RADIUS server and acts on the response it receives. The server, on the other hand, is responsible for receiving user access requests, authenticating and authorizing users, and returning all of the necessary configuration information the client can then pass on to the user.


Figure 4-17 PEAP Sample Deployment

Figure 4-17 displays a Windows XP client trying to associate with a wireless access point—the first step the client performs. The second step is that the access point in Figure 4-17 blocks the request because the client has not been verified by the RADIUS server.

Figure 4-18 displays the next six steps in the PEAP authentication process.


Figure 4-18 PEAP Authentication Process

The eight-step process in Figure 4-17 and Figure 4-18 starts with the clients' attempt to authenticate with the RADIUS server. Once a valid username and password are exchanged, the RADIUS server and client establish a common key used to send and receive data over a secured wireless connection.

The Cisco Wireless Security Suite supports IEEE 802.1X authentication and numerous EAP types, including EAP Cisco Wireless (LEAP); EAP-Transport Layer Security (EAP-TLS), and types that operate over EAP-TLS, such as PEAP, EAP-Tunneled TLS (EAP-TTLS), and EAP-Subscriber Identity Module (EAP-SIM). The suite also supports a pre-standard version of Temporal Key Integrity Protocol (TKIP).

TKIP defends against an attack on Wired Equivalent Privacy (WEP) in which the intruder uses an unencrypted segment called the initialization vector (IV) in encrypted packets to calculate the WEP key. TKIP removes the predictability that an intruder relies on to determine the WEP key by exploiting IVs. TKIP protects both unicast and broadcast WEP keys.

TKIP provides enhancements to 128-bit encryption. One such enhancement is per-packet key hashing, where the encryption key is changed on each packet. This feature helps combat a common WLAN hacking tool called AirSnort, freely available at http://airsnort.shmoo.com/, which takes advantage of a weakness in WEP encryption when static WEP keys are not changed during a session. It must be pointed out, however, that even with TKIP, the session key needs to be changed before the IV space recycles at 16.7 million packets.

Another important new security advance with TKIP is Message Integrity Check (MIC). With MIC, a digital signature is included with every frame sent, neutralizing the man-in-the-middle attack by hackers who can capture a wireless packet, modify it, and resend it.

TKIP and MIC are easily deployed on an access point. The following list details the simple three-step IOS configuration process:

Step 1.

Enter global configuration mode:

configuration terminal
Step 2.

Enter interface configuration mode for the radio interface:

interface dot11radio 0
Step 3.

Enable WEP, MIC, and TKIP:

encryption [vlan 
         vlan-id] mode wep {optional [key-hash] | mandatory [mic]
8. Virtual Private Dial-Up Networks (VPDN) | Next Section Previous Section

Cisco Press Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Cisco Press and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Cisco Press products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@ciscopress.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by Cisco Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.ciscopress.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020