Path in Cisco Documentation

cisco.com/go/support –> Switches –> Nexus 9000 –> Troubleshooting Guides –> (select NX-OS release) –> “Cisco Nexus 9000 Series NX-OS Troubleshooting Guide, Release …” –> Troubleshooting Installations, Upgrades and Reboots –> Chapter Contents –> Troubleshooting Software System Reboots –> Recovery from the loader> Prompt.

Assumption 1: NX-OS File in Bootflash

Loader> dir
<you see for example nxos.9.3.13.bin NX-OS file in the bootflash>
Loader> boot nxos.9.3.13.bin

The system should boot the image. When you get the normal prompt, make sure to set the bootvariable to that NX-OS image:

preparing the work environment

First, I have the habit of working in virtual environments. I create one and activate it:

Wassim@linux:~/private/labscripts$ python -m venv venv
Wassim@linux:~/private/labscripts$ ls
venv
Wassim@linux:~/private/labscripts$ source venv/bin/activate
((venv) ) Wassim@linux:~/private/labscripts$

I initially wanted to install a virtual environment for Linux and another one for Windows in the same directory. It looks like the installer failed me silently. No exe or bat files were installed. So, I deleted the venv directory that I created weeks ago on my Linux machine using rmdir /S, and recreated it on Windows with python -m venv .\venv.

SSH on Cisco devices

SSH Terminal-Line Access Feature

replaces reverse Telnet feature that was typically configured on terminal services routers.

provides secure console access for servers physically connected to a terminal services router.

introduces the concept of ‘rotary’.

Remember that each physical Async port has an associated logical line to it.

Each router line (not the Async ports) must be configured with a unique rotary number.

Number of rotaries == number of lines

VPN Advantage

A VPN is a network where private network services are provided to one or more customers over a public network, Internet, or a private network. 

A VPN consists of one or more VPN tunnels! 

VPN connects sites of a same customer together.  A set of “policies” determine which sites communicate with each other and which not;  

In one scenario, the customer itself defines and implements them, in collaboration with the SP. The customer may for example want to force traffic from site S1 to traverse site S2, because the latter has a firewall installation. 

While performing routine configuration on a Cisco router, I encountered a funny typo. Try to find it by yourself. Hint: it’s in the last line.

There’s an info on the Internet that says it’s possible to pass Vmware VCA certs for free. It’s been a while now and Vmware retired this offer.

However, there are some folks that say they could get around and pass without spending a penny. They say it’s a matter of combining promo codes.

I’ve been trying all the codes. Pearson Vue warned me that they’re going to shut down my account if I do another attempt.

In this tutorial we’ll learn :

• How to push an IOS image into a switch flash disk, using Cisco LMS,
• How to verify that the IOS image has been loaded correctly

Pushing the IOS image

1. On the LMS home page, click on the Resource Manager Essentials link.

2. Click on Software Distribution

3. Choose a distribution method. By default, I use “by device”. That’s the simplest one

4. Check the device for which you want to upgrade the IOS and click Next

Today I successfully passed the exam. I got a score of 420. Alhamdulillah.

How I studied for the exam: I watched the Vmware E-learning fundamental videos, took notes, reviewed them with a big mind map, then registered and sat for it. I sat studying in many small sessions.

It’s great to sit for an exam and pass it from home :) it’s also great to see there are other folks out there who are sharing the same experience.

Players: Catalyst switch with PoE support, Cisco IP phones Script: We want to check whether there still is enough amount of PoE energy, on a Catalyst switch. Solution: do a “show power inline”, check the “Remaining” column.

Situation I tried to register my MGCP gateway to my CUCM, but everytime I did a “show ccm-manager”, it displays the following: Troubleshooting I first thought about an issue about DNS on CUCM. I remembered that, during the CUCM installation, I put CUCM somewhere. So I went to every corner of CUCM admin pages, where I could find the “CUCM” keyword. I changed some settings in Entreprise Parameters. I even tried to change the hostname under the CUCM CLI mode: Then, I examined what’s happening at the router level, with “debug mgcp events”. I noticed this line: