Home > Articles > Certification > Cisco Certification > CCIE

This chapter is from the book

Foundation Summary

The "Foundation Summary" is a condensed collection of material for a convenient review of this chapter's key concepts. If you are already comfortable with the topics in this chapter and decided to skip most of the "Foundation Topics" material, the "Foundation Summary" will help you recall a few details. If you just read the "Foundation Topics" section, this review should help further solidify some key facts. If you are doing your final preparation before the exam, the "Foundation Summary" offers a convenient and quick final review.

Table 4-8. AAA Terminology

Attribute

Meaning

Authentication

Who are you? A remote user must be authenticated before being permitted access to network resources. Authentication allows users to submit their usernames and passwords, and permits challenges and responses. Username/password pairs are a common form of authentication.

Authorization

What resources are you permitted to use? Once the user is authenticated, authorization defines what services in the network the user is permitted access to. The operations permitted here can include IOS privileged EXEC commands.

Accounting

What resources were accessed, at what time, and by whom, and what commands were issued to access them? Accounting allows the network administrator to log and view what was actually performed; for example, if a Cisco router was reloaded or the configuration was changed. Accounting ensures that an audit will enable network administrators to view what was performed and at what time.

Table 4-9. RADIUS Summary

Feature

Meaning

UDP

Packets sent between clients and servers are UDP primarily because TCP's overhead does not allow for significant advantages. Typically, the user can wait for a username/password prompt.

UDP destination port

Early deployments of RADIUS used UDP ports 1645 and 1646. The officially assigned port numbers are 1812 and 1813.

Attributes

Attributes are used to exchange information between the NAS and client.

Model

Client/server-based model in which packets are exchanged in a unidirectional manner.

Encryption method

The password is encrypted using MD5; the username is not encrypted. RADIUS encrypts only the password in the access-request packet, sent from the client to the server. The remainder of the packet is in clear text. A third party could capture other information, such as the username, authorized services, and accounting information.

Multiprotocol support

Does not support protocols such as AppleTalk, NetBIOS, or IPX. IP is the only protocol supported.

Table 4-10. TACACS+ Summary

Feature

Meaning

TCP

Packets sent between client and server are TCP.

TCP destination port

Port 49.

Attributes

Packet types are defined in TACACS+ frame format as follows:

Authentication 0x01
Authorization 0x02
Accounting 0x03

Seq_no

The sequence number of the current packet flow for the current session. The Seq_no starts with 1, and each subsequent packet increments by one. The client sends only odd numbers. TACACS+ servers send only even numbers.

Encryption method

The entire packet is encrypted. Data is encrypted using MD5 and a secret key that matches both on the NAS (for example, a Cisco IOS router) and the TACACS+ server.

Multiprotocol support

Supports protocols such as AppleTalk, NetBIOS, or IPX. IP-supported only.

Table 4-11. RADIUS Versus TACACS+

 

RADIUS

TACACS+

Packet delivery

UDP

TCP

Packet encryption

Encrypts only the password in the access-request packet from the client to the server.

Encrypts the entire body of the packet, but leaves a standard TCP header.

AAA support

Combines authentication and authorization.

Uses the AAA architecture, separating authentication, authorization, and accounting.

Multiprotocol support

None.

Supports other protocols, such as AppleTalk, NetBIOS, and IPX.

Router management

Can pass a privilege level down to the router, which can then be used locally for command authorization.

Enables network administrators to control which commands can be executed on a router.

Table 4-12. Encryption Methods

Encryption Method

Description

Data Encryption Standard (DES)

A block cipher algorithm, which means that it performs operations on fixed-length data streams. Uses a 56-bit key to encrypt 64-bit datagrams. DES is a published, U.S. government-approved encryption algorithm.

Triple DES (3DES)

A variant of DES that iterates three times with three separate keys (encrypts with one 56-bit key, decrypts with another 56-bit key, and then encrypts with another 56-bit key).

Three keys are used to encrypt data, resulting in a 168-bit encryption key.

Advanced Encryption Standard (AES)

A new standard that replaces DES. Encryption key lengths are 128, 192, and 256 bits.

Table 4-13. IKE Phase I/II

Phase

Tasks

IKE phase I

Authenticates IPSec peers

Negotiates matching policy to protect IKE exchange

Exchanges keys using Diffie-Hellman

Establishes the IKE security association

IKE phase II

Negotiates IPSec SA parameters by using an existing IKE SA

Establishes IPSec security parameters

Periodically renegotiates IPSec SAs to ensure security and that no intruders have discovered sensitive data

Can also perform optional additional Diffie-Hellman exchange

Table 4-14. IPSec Terminology

Term

Meaning

Internet Key Exchange (IKE)

A protocol that provides utility services for IPSec, such as authentication of peers, negotiation of IPSec SAs, and encryption algorithms.

Security association (SA)

A connection between IPSec peers. An SA is unidirectional, and two SAs are required to form a complete tunnel.

Message Digest 5 (MD5)

A hash algorithm (128 bit) that takes an input message (of variable length) and produces a fixed-length output message. IKE uses MD5 or SHA-1 for authentication purposes.

Secure Hash Algorithm (SHA-1)

A hash algorithm (160 bit) that signs and authenticates data.

RSA signatures

RSA is a public-key encryption system used for authentication. Users are assigned both private and public keys. The private key is not available to the public and is used to decrypt messages created with the public key. To have a signature validated you need to have a CA sign the public key, making it a certificate.

Certificate Authority (CA)

A trusted third party whose purpose is to sign certificates for network entities it has authenticated.

Authentication Header (AH)

Used to authenticate data. AH provides data origin authentication and optional replay-detection services.

Encapsulating Security Payload (ESP)

ESP (transport mode) does not encrypt the original IP header, and only encrypts the IP data by placing a header in between the original IP header and data. ESP (tunnel and transport modes) provides data confidentiality, data integrity, and data origin authentication.

Diffie-Hellman (DH)

Algorithm that is used to initiate and secure the session between two hosts, such as routers.

Advanced Encryption Standard (AES)

A new encryption standard that is considered a replacement for DES. The U.S. government made AES a standard in May 2002. AES provides key lengths for 128, 192, and 256 bits.

Table 4-15. Enabling TKIP on an Access Point

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] [key-hash]}

InformIT Promotional Mailings & Special Offers

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

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about 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.

Surveys

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.

Newsletters

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

Security


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

Children


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

Marketing


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.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. 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.informit.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.

Links


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