Friday, July 04, 2008

It's Friday, July 4, and here are the answers to yesterday's Cisco CCNA, CCENT, CCNA Security, and CCNP practice exam questions!

Check today's other blog postings for the latest on the new CCNA Voice, Wireless, and Security certifications - including a new CCNA Security tutorial and the announcement of my new CCNA Security Study Package!

CCNA Certification:

Convert the hex value "Cd" into both a decimal value and binary string.

Decimal: We have 12 units of 16 and 13 units of 1; that's 205.

Binary: 205 = 11001101

CCNA Security:

What is the net effect of this command?

R1(config)#aaa authentication login default group radius group tacacs

Answer: The group radius and group tacacs commands configure the router to use those devices for Authentication - but it's interesting that we were able to configure more than one Authentication source.

Actually, we can name a maximum of four methods, and they'll be used in the order listed. In the above command, the default list will check the RADIUS server first. If there's an error or a timeout, the second method listed will be checked.

If a user's authentication is refused by the first method, the second method is not used, and the user's authentication attempt will fail.

CCENT Certification Question:

Name the layers of the TCP/IP networking model and describe how those layers map to the OSI model.

Answer: Going from top to bottom, the Application layer of the TCP/IP Model maps to the Application, Presentation, and Session layers of the OSI model.

The Transport layer in the TCP/IP model maps to the Transport layer in the OSI model.

The Internetworking (or Internet) layer of the TCP/IP model maps to the Network layer of the OSI model.

Finally, the Network Access Layer of the TCP/IP model maps to the Data Link and Ethernet segments of the OSI model.


What makes a floating static route "float"?

A floating static route is a backup method that is relatively simple to configure. The static route will be exactly the same as a dynamically discovered route in the routing table, but will have a higher administrative distance than that of the dynamic route. That higher administrative distance causes that static route to "float".

If the dynamic route leaves the table, the floating static route will be put into the table in its place; when the dynamic route returns, the floating static route will be removed.


What is an Etherchannel? Why do we use them? What physical limitations should be considered when configuring one?

Answer: An etherchannel is a logical bundling of physically separate trunk links. Bundling them allows us to use all available paths between two switches, since the etherchannel is seen as a single connection by STP. If we don't bundle them, only one of the paths will be available and STP will put the rest of them into blocking mode.


Name the four available severity levels for IPS signatures.

Answer: High, Information, Medium, Low.

CCNP / ONT Exam:

You can configure TCP header compression and RTP header compression in "passive mode". What's the net effect of doing so?

Answer: Configuring TCP passive compression means that outbound packets only have their TCP headers compressed if that same interface is receiving packets with their TCP headers compressed. RTP header compression works the same way (with RTP headers rather than TCP headers, naturally).

New questions later today!

To your success,

Chris Bryant
CCIE #12933

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