Posts Tagged ‘CCNA’

CCNA Voice Tutorial – DHCP and the IP Phone Boot Process

by Chris Bryant - 15 October 2009

Just as our switches and routers have certain tests and procedures they run when they boot, so do Cisco IP Phones – but of course, there’s a major difference or two between the Phone and router boot processes!

Here’s the basic boot procedure for a Cisco IP Phone:

As you’d expect, the first step is to physically connect the Phone to a switch port. The Phone can receive its power via Power Over Ethernet (PoE) if the Phone and Switch agree on the PoE method to be used. Originally called “inline power”, PoE allows the power to be sent through the copper cable to the connected device.

Our old friend Cisco Discovery Protocol enters the picture now, as its CDP that tells the Phone what Voice VLAN to use. Be sure CDP is running on the switch port that’s connected to the IP Phone, as it’s commonplace to disable CDP.

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CCNA Security Exam Tutorial – When It’s Good to Add Salt

by Chris Bryant - 2 February 2009

When you started studying for your CCNA certification exam, one of the very first things you learned was the major difference between the enable password and the enable secret – the enable secret is encrypted by default, where the enable password is just sitting there in clear text, waiting to be read!

When you look at the enable secret in a Cisco router configuration, it looks like it would be impossible to guess. After setting the enable secret on this router to the word security, here’s how it appears in the configuration:

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Cisco CCNP Certification exam tutorial – Knowing RADIUS and TACACS for your ISCW Exam

by Chris Bryant - 19 May 2008

Cisco switchesAs part of your CCNP certification exam studies, particularly for the ISCW exam, you need to be very clear on the differences between TACACS+ and RADIUS.

As a CCNA and future CCNP, you’ve already configured authentication in the form of creating a local database of usernames and passwords for both Telnet access and PPP authentication. This is sometimes called a self-contained AAA deployment, since no external server is involved.

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