Networks Guru

Category: General

Configuring and Troublshooting NTP on a Cisco IOS Router

Notte: This article assumes you already know what is the NTP protocol and its related concepts.

Configuring a cisco IOS router as an NTP client requires implementing the below commands,
1. Setting up the timezone, in this case we’ll consider Italy’s timezone which is CET (GMT +1)
We’ll set the dayklight savins using the summer time-zone command

clock timezone CET 1
clock summer-time CEST recurring

2. Configuring the NTP server & it can be inserted as an IP in case it’s an internal Server or a public server with a static IP

Creating a dummy Interface on a Linux/Unix based Systems

A dummy interface maybe created for various reasons like:

  • Publishing Services
  • A 2nd loopback interface with a public IP

Parsing a list of IPs and/or Networks with Prefix-Length or Subnet Masks

A very simple script that uses ipcalc capabilities to parse a list of IPs or networks an outputs a list of readable Network IDs with their subnet masks.



Installing Running and Troubleshooting GNS3 1.3.3 IOU on Ubuntu 15.04

Starting with the video,

Continuing with the road-map and the correspondent steps

1- Install iouyap
sudo apt-get install git bison flex
git clone
cd iniparser
sudo cp libiniparser.* /usr/lib/
sudo cp src/iniparser.h /usr/local/include
sudo cp src/dictionary.h /usr/local/include
cd ..
git clone
cd iouyap
sudo make install

2- Install vpcs

sudo apt-get install vpcs

3- Add IOU virtualbox image

-Change hostname
-Config static IP
-Add 2nd Interface
-Edit Sources.List
-Install Python2.7

4-Connecting IOU VM to GNS3
5-Running and Testing the new setup


Finally, Please note that the .iourc file has been uploaded with the correct type later on before continuing with the vid.

Installing GNS3 1.3.3 on Ubuntu 15.04

Starting with the video,


The commands used in this video below,

before starting with the installation , Please confirm that you have Python 3.3 or more using this command   python3 -v if not please download and install it either by visiting python’s website or by using the below command

sudo apt-get install python3.4.3

also make sure that gcc is installed using

sudo apt-get install gcc

GNS3 GUI – Part1 :

sudo apt-get install python3-setuptools
sudo apt-get install python3-pyqt4
cd gns3-directory
sudo python3 install

GNS3 Server – Part2:

sudo apt-get install python3-setuptools
sudo apt-get install python3-netifaces
cd gns3-directory
sudo python3 install

Dynamips – Part3:

sudo apt-get install cmake
apt-get install libelf-dev
apt-get install uuid-dev
cd dynamips-directory
mkdir build
cd build
sudo cmake ..
sudo make install

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