Category: Cisco

CCNA Security (640-553)

by Sensei Email

Diploma
I passed. Even though I'm working toward my CCIE Routing and Switching, I knew this wouldn't be a chump test. There's only so much I can say about it under the NDA, but here's my results and the steps leading up to it.

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Cisco In-band Password Recovery Using TFTP & SNMP

by Sensei Email

Lifesaver
We inherited a legacy network in a remote location, configured with a dead AAA server, and local user accounts that no one had the password to. I knew the "enable secret" and VTY password, but the local accounts were preventing me from ever getting to use them. What I did have at my disposal, was knowledge of the read/write SNMP string and access to a server listed in the ACL for it.

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Basic Cisco Troubleshooting Cheatsheet

by Sensei Email

Flowchart
Here's a list of commands and some examples of output, as well as some general Cisco errata. This is typically something I distribute when doing training for people at a CCNA level or lower. I'll be putting together a more advanced one more applicable to a CCNP level.

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Remote Upgrades Using X-Modem Transfers Over TCP/IP

by Sensei Email

X-Modem Transfer
We've got some devices that you can perform a system image upgrade via X-modem transfer over the serial port. Various reasons make this desirable in our environment, but there's one drawback... who wants to be standing in front of a load-balancer in an early-morning maintenance window with a serial cable hooked up to their laptop? Thanks to the Cisco-based console solution, there's another way. Following these simple steps, you can kick off an X-modem transfer remotely.

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How "Reverse Telnet" Works

by Sensei Email

I never cared much for the term "reverse telnet." When you get right down to it, "IP-to-Async Redirection" or "Serial Pass-through" would be far more accurate, but they all amount to the same thing for the same reason. Remote console access.

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