Kali Linux VMware tools install

Installation VMware tools allows better performance of the Virtual Machine in this case Kali Linux.

Depending on VMware you are running i.e Workstation,Vsphere client or Fusion  location the VMware tools install location will be different. The below location is for VMware Fusion.

CLICK install VMware tools (has Reistall VMware Tools as it is already installed).

Screen Shot 2017-08-30 at 7.26.53 pm.png


Once Vmtools appears on dektop open folderScreen Shot 2017-08-30 at 7.22.41 pm.png

Drag Vmware tools.tar.gz file to desktop.

Screen Shot 2017-08-30 at 7.23.12 pm.png

Than  disconnect Vmware tools by hit eject bottom left corner of  folder.

Screen Shot 2017-08-30 at 7.23.27 pm.png


  • cd Desktop/
  • ls (to locate VMware specific file)
  • tar -cf vmwareTools-10.1.6-521329.tar.gz
  • ls (to locate VMware specific file)
  • cd vmware-tools-distrib/
  • ls
  • perl vmware-install.pl -d

Screen Shot 2017-08-30 at 7.23.33 pm.pngScreen Shot 2017-08-30 at 7.23.44 pm.png

once installation is complete reload Kali Linux


  • reboot


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Cisco Channel bonding


The following channel width options are recommendations for use in  Enterprise wireless networks.

Frequency Channel width
2.4GHz 20MHz
5GHz 20MHz & 40MHz*


* If 40MHz wide channels are required, the following tests listed below should be performed before moving to or deploying 40MHz wide channels*.

  •  RF spectrum analyse will be required to ensure available spectrum and issue such as co-channel and adjacent channel interference are correctly managed.
  •  If changing channel widths, a passive and active wireless site survey will be required to be perform to ensure coverage or capacity is not affected.
  •  Aggregate data throughput testing will be required for justification of utilising 40MHz wide channels.

Channel width cans be adjusted in the following methods list below.

To configure channel width globally, perform the following steps:

  1. Wireless> 802.11an/n/ac> RRM>DCA
  2. Channel width> selected suitable width 20MHz or 40MHz
  • If selecting 40MHz wide channels ensure that at least two adjacent channels(primary and secondary) are selected form the DCA channel list
  1. Apply settings and save configuration

Screen Shot 2017-08-26 at 8.27.11 am.png

Figure 1 Global channel width configuration

RF profiles can also be applied to groups of APs that share a common coverage zone i.e. floor Depending on you wireless requirement you can customers or use default profile settings.

To change the Channel width

  1. Wireless>RF Profiles
  2. Create or used default profile
  3. RRM> click on channel and click Apply

Screen Shot 2017-08-26 at 8.27.24 am.png

Figure 2 RF profile

RF profile can be applied to an AP group with the required channel width and custom or default profile.

Antenna Types overview

Antenna types fall into 3 main categories

  • Omnidirectional
  • Semi-directional
  • Highly directional


Which will be discussed below.

Omnidirectional Antennas

Omnidirectional antennas radiate RF signal in all directions, a typical omnidirectional antenna is dipole antenna, that has a radiation pattern similar to figure 1.

Screen Shot 2017-08-13 at 12.50.22 pm.png

Figure 1: Omnidirectional Antenna propagation pattern


Omnidirectional antenna  are designed to provide coverage in all directions, the horizontal beamwidth of  360 degrees and the vertical beamwidth can range from 7 to 80 degrees, depending on antenna used.

Omnidirectional antennas are often used in following deployments

  • Point to multipoint: A omnidirectional antenna is connected to a transceiver device that propagates it RF signal similar to  figure 1. to multiple transceivers
  • Wireless mesh deployment: provides a wireless network that allows network ingress locations where wired infrastructure is not available or possible. Wireless meshed networks provide multiple backhaul links, providing redundancy in the even one of the wireless nodes fails
  • Indoor 802.11 wireless networks: wireless 802.11 access points can have internal or external omnidirectional antennas depending on the environment that they are to be used in. for example a corporate office  would use access points with internal antennas for cosmetic reasons where a warehouse would have access points with external high gain antennas mounted at height to provide more coverage


Semi directional Antennas

Semi directional antennas are often used to direct signals in certain direction. i.e. down walk ways or warehouse aisles.  where the signal requires a specific coverage as well they can be used  in short-to-medium distance links i.e. between two buildings.

Semi directional antennas are unlike omnidirectional that propagates in all directions.

Screen Shot 2017-08-13 at 12.50.34 pm.png

Figure 2: Semi directional  Antenna propagation pattern

Common types of semi directional antennas are

  • Yagi
  • Patch
  • Panel
  • Sector

Highly directional antennas

Are to used for point-to-point communications which required a much narrower beamwidth to cover larger distances.

Screen Shot 2017-08-13 at 12.50.43 pm.png

Figure 3. Highly directional Antenna propagation pattern

Two types of highly directional antennas

  • Parabolic dish antenna
  • Grid antenna


J.L. Olenewa (2014). Guide to Wireless Communication (Third Edition). Boston:CENGAGE Learning

D.A Westcoot, D.D Coleman (2014). Certified Wireless Network Administrator (Fourth Edition).Indianapolis: John Wiley & Sons, Inc.

CWNA certification, is it worth it?

If you are reading this you have idea of what the CWNA (certified wireless network administrator) is and what CWNP offer but if not this is straight from the website.

“At CWNP, we offer Enterprise Wi-Fi certifications for entry-level professionals all the way up to seasoned network experts. Each certification level is designed to benchmark your deepening understanding of RF technologies and applications of 802.11 networks. The CWNA certification will teach you the fundamentals  to be a competent Wireless engineer. The topics covered in the certification including RF fundamentals and components, wireless LAN topologies and access, intrusion monitoring, attacks, troubleshooting, and many other essential topics and concept”.

Having been in the communication field for over 11 years having done my trade as a telecommunication technician in the Army, I had not heard of the CWNA certification or for that matter the CWNP  company, until one day I was in conversation with a tech from another company, and we got on to the topic of wireless certifications.

I told him I was studying for the CCNA wireless certification, as I was doing a lot of Cisco wireless in my current role.  He mentioned that I should look into CWNA certification as its vendor neutral and provides a deeper understanding of all things 802.11.

This caught my interest as I wanted to have a good foundation of 802.11 with out all the extra vendor specific information. At lunch time I googled the CWNA and discovery what the CWNP had to offer, I instantly new this was the certification track that I wanted to embark on. So once pay day came around I bought myself a copy of the  CWNA eBook. (funds where short that week) and started reading.

The material in the book was excellent and well written. After a few months of on and off reading ,I start looking into the certification exam and the value it would add to my CV, as a I was trying change job roles within the company I work for.

To get a understanding of the worth of the qualification I starting searching forums and employment sites and came to the conclusion it was not in demand or well known in my country (Australia).

So I decided to focus my studies on completing  the CCNA Wireless exam, as I felt it would add to my CV, as I currently held a CCNP Route & Switch.

After many months of study  I successfully completed the exam, and  eventually move to an new position.  During the first few months in this new role and to this day, I still  continually reference back to the CWNA book for wireless information.  So I decided to knuckle down and study for the exam, not to add wait to my CV  but for myself as the information learnt from studying for this certification will make you a better wireless engineer.

After 6months + of hard study,  I sat the exam  and walked out with a  98% pass mark. I was blown away by my pass mark,  I put it down to the fact that I loved reading the material which made grasping the topic so much more easier.

I  strongly believe that if you are interested in learning wireless (802.11),  the CWNP training and certification track is the path you must go down.











Cisco WLC HA Pair

Cisco High Availability pair configuration

I did this how to blog post to show the steps I took to configure 2x 5508 Wireless LAN Controllers as part of a High availability (HA) pair.

A more detail explanation can be found at Cisco.com.

Some techie information about HA .The High availability feature will allow for stateful switchover of the Cisco Lightweight Access Points and client sessions from the active Wireless LAN Controller (WLC) to the standby WLC.

Client SSO enables client information to be synced to the standby controller when client association or settings change. Making no noticeable network outage in the event of the primary controller failing

 Prerequisites for HA configuration:

      • Same software version
      • min of 50 AP license  on both controller or a HA SKU WLC

 Screen Shot 2017-08-04 at 5.34.05 pm.png

 Step 1:click on “CONTROLLER” TAB

Screen Shot 2017-08-04 at 5.34.12 pm.pngStep 2: Click on “Redundancy”  and then click “Global Configuration”

Screen Shot 2017-08-04 at 5.34.17 pm.png

Figure 3:Redundancy  global configuration

Step 3: Enter the IP address for “Redundancy Mgmt” and  “Peer Redundancy Mgmt”

Step 4: Select “Primary” or “Secondary”  for Redundant unit

Step 5: Click “Apply”

Step 6: Click “Enabled”  for SSO (ensure  UTP cable is plugged in to the Redundant port between  both WLC )

Connection between the two WLC’s is made by the redundancy port on both of the WLC, (picture below is off  5520 model, 5508 Redundancy ports are on the front of the controller)

Screen Shot 2017-08-04 at 5.34.24 pm.png


The Redundancy Management Interface is configured in the same subnet as the management interface. Once the Active WLC does not respond to Keepalive messages on the redundant port. The interface will check the health of the Active WLC via the Network infrastructure. This provides an additional health check of the network and Active WLC and confirms if switchover should or should not be executed.

The interface is used for Bulk configuration during boot up and incremental configuration are synced from Active WLC to the Standby WLC using the redundant port. The port will perform HA role negotiation and is also used in order to check peer reachability, sending UDP keep-alive messages every 100msec (default timer) from the Standby WLC to the Active WLC.

Layer 2 Connection can be used between the Redundancy port of the Primary and Standby WLC, as it does not require a direct connection.

Step 7: Click “apply” the WLC’s will reboot and start the negotiation

Screen Shot 2017-08-04 at 5.34.28 pm.png

**If the Standby WLC does not detect the Primary WLC after 120seconds it will boot into “maintenance mode” Reboot Standby controller again.

Once the WLC ‘s are synced the WLC 1  (Primary) will be in an active state.

WLC2 has success become part of HA indicated by ”STANDBY HOT” state


All Management of the WLC’s will be done on the Primary WLC (WLC1) as WLC2 (Standby Hot) management interface will not work, only way to access is via console connection or via SSH on the service port and on the redundant management interface.

Screen Shot 2017-08-04 at 5.34.35 pm.png

Step 8:  To Check the High Availability (SSO)  configuration was successfully, form the Monitor page click “Redundancy” and the click “Summary” if configuration was successful the output will look similar to below.

Screen Shot 2017-08-04 at 5.34.42 pm.png

Step 9: if there is issues with High availability (SSO) configuration it will display the following

Screen Shot 2017-08-04 at 5.34.46 pm.png

Step 10: Plug console into the Standby controller

      • To Display HA information in the CLI enter “ show redundancy summary”.

Screen Shot 2017-08-04 at 5.34.53 pm.png

If the Peer state indicates- Communication Down refer to the below steps.

      • Check Redandant port cable is connected correctly. “As per step 6”
      • If connected correctly test cable or replace with new cable.
      • Check both WLC’s are the same version and have the minimum AP licence required of 50+
      • Check IP address settings

Once fault has been found and if the standby controller does not reboot self after a few minutes  do a manual power cycle and watch the console output  for the  the following.

Screen Shot 2017-08-04 at 5.34.59 pm.png

Once reloaded, repeat the steps to check the HA configuration.

Upon successful completion of the above steps. Perform required network connectivity test i.e ping test by clicking on the Ping tab in the top right hand of the WLC webpage.


 Screen Shot 2017-08-04 at 5.35.05 pm.png


Cisco Wireless LAN Controllers configured as a High availability pair.

Components of a Radio system

A basic construction of a typical radio system consist of filters, mixers amplifiers and antennas.

Filter: removes all unwanted signals from a Radio frequency signal. It either allows the signal to pass through or blocks the signal based on it frequency configuration.

There are 3 types of RF filters

  • Low-pass: a max frequency is set and all signals below that are allowed to pass through
  • Bandpass: has a minimum and a maximum threshold range signals that fall within the threshold are allowed through
  • And high pass: sets a minimum frequency threshold, all signals above the minimum threshold are allowed to pass through.

Filters are also found in transmitters, where they are used to eliminate unwanted frequencies called harmonic oscillations, which result from the process of modulating the signal before transmission.

Mixers: combine two inputs and create one output. The single output of a mixer is in the range of the highest sum and the lowest difference of the two frequencies. The sum and the difference are know as sidebands of the frequency carrier because the fall above and below the centre frequency of the carrier signal.

Mixers are used to convert an input frequency to a specific desired output frequency.

Amplifier: An amplifier is used to increase amplitude of an RF signal. A Amplifier is the last stage in a radio circuit and its function is to boost the power of the signal received from the last filter stage before it is transmitted.

Antennas: for a RF signals to be transmitted and received, the transmitter or receiver must be connected to an antenna.(refer to blog on Antenna types)

J. L. Olenewa (2014). Guide to Wireless Communications, ( Third Edition). Boston:CENGAGE Learning

Analog Modulation

Analog modulation: The carrier signal sent in analog radio transmission is simply a continuous electrical signal. It carries no information and is referred to as a CW. Only when the CW is modulated is it called a carrier. Analog modulation is the representation of analog information by an analog signal. There are three types of modulation that can be applied to a analog signal to enable it to carry information. The height of the signal, the frequency of the signal and the relative starting point, or phase of the signal.

Amplitude Modulation (AM): the height of a wave, know as amplitude, can be measured in volts (electrical pressure) .  In Amplitude modulation (AM) the height of the wave is changed in accordance with the height of  another signal, called the modulating signal. AM is very susceptible to interference from outside sources such as lighting , it is general not used for data transmissions.

Screen Shot 2017-08-01 at 7.16.52 pm.png Figure: Amplitude of a signal

Screen Shot 2017-08-01 at 7.16.46 pm.pngFigure: Amplitude modulation(AM)

Frequency Modulation (FM):  In Frequency modulation (FM) , the number of waves that occur during one second undergoes change based on the amplitude  of the modulating signal while the amplitude and the phase of the carrier remain constant.

FM is not as susceptible to interference from outside sources and is most commonly used to broadcast radios programs. An FM carrier has a wider  bandwidth, which allows it to carry Hi-Fi as well as stereophonic signals, with two separate sound channels.

Screen Shot 2017-08-01 at 7.16.29 pm.png

Figure: Frequency modulation (FM)

Phase Modulation: In contrast to AM, which changes the height of the wave, and FM which increase the number of waves per cycle, phase modulation (PM) changes the starting point of the cycle, while the amplitude and frequency of the carrier remain constant. Phase modulation is not generally used to represent analog signals.

A signal composed of sine waves has a phase associated with it. The phase is measured in degrees and one complete wave cycle covers 360 degrees. A phase change is always measured with reference to some other signal.

J. L. Olenewa (2014). Guide to Wireless Communications, ( Third Edition). Boston:CENGAGE Learning

What is an Antenna

Antennas are used to transmitted and receive radio waves. An antenna is a length of copper wire or similar material, with one end free and the other end connected to a receiver or transmitter. When transmitting the radio waves created by the electronic circuit of the transmitter are fed to this antenna. This sets up an electrical pressure (voltage) along the wire, which will cause a small electrical current to flow into the antenna. Because of the current is alternating , it flows back and forth in the antenna at the same frequency as the radio waves,  it creates both a magnetic field and an electrical field around the antenna. This continuous (analog) combination of magnetism and electrical pressure moves away (propagates) from the antenna . The results is an electromagnetic wave(EM wave).

J. L. Olenewa (2014). Guide to Wireless Communications, ( Third Edition). Boston:CENGAGE Learning

Wireless Personal area network

What is a WPAN?

WPAN standards for Wireless personal area network, it consist of a group of short range communication  devices that work from distance from a few inches to 10m  and can on occasion reach up to a distances of 30m.

WPAN are usually designed for  data transmission that do not required high data throughput.

WPAN has 3 advantages;

  • Reduce the  need for cables and wires
  • Do not require much power due low out put transmitting power making battery life last for much longer.
  • Due to distance limitation it has somewhat better security and privacy compared to other wireless technologies.

WPAN technology can consist  but are not limited to the following below types devices

  • portable data exchange devices
  • Home control systems
  • audio head sets
  • industrial control systems
  • home security systems
  • RFID tags
  • inventory and asset tracking

Pyles, J. Carrell, J.L. Tittel, E. (2013). Guide to TCP/IP: IPv6 and IPv4 (Fifth Edition). Boston:CENGAGE Learning

Wireless Signals

The following information is based on my UNI studies on wireless communication systems.

Wireless Signals: All forms of electromagnetic energy- gamma rays, radio waves, even light- travel through space in the forms of waves. These waves are know as electromagnetic waves. They travel at the speed of light :186,000 miles per second (300,000 kilometres).

802.11 use wireless transmission use electromagnetic (EM) waves as the medium, not air or empty space

There are two basic types of waves by which wireless data are sent and received: infrared light and radio waves. Infrared light some of which is invisible, has many characteristics that visible light has , because it is adjacent to visible light on the light spectrum. Yet it is a better medium for data transmissions because it is less susceptible to interference from other sources of visible light.

Each wave length within the spectrum of visible light represents a particular colour. This because  the differing wavelengths of light waves bend at a different angle when passed through a prism. Which in turn produces different colours. The colours that visible light produces are red, orange, yellow, green, blue, indigo, and violet. Visible light is sometime referred to as ROYGBIV.

Infrared wireless systems require that each device have two components: an emitter, which transmits a signal, and a detector, which receives the signal. An emitter is usually a laser diode or a light-emitting diode(LED). Infrared wireless systems send data by the intensity of the light wave. The emitter sends a narrowly focused beam of infrared light.

(TV remote is an example of this type of device)

Infrared wireless transmission can be either directed or diffused. A directed transmission requires that the emitter and detector be directly aimed at one another( line of sight).

A diffused transmission relies on reflected light. With diffused transmission the emitters have a wide focus beam instead of a narrow beam.

Infrared  wireless systems have several advantages. Infrared light neither interferes with other types of communications signals(such’s as radio waves) nor is it affected by other signals. Expect light.

Infrared wireless light does not penetrate wall, the signals are kept inside a room, this makes it impossible for someone else to listen in on the transmission signal.

Infrared wireless systems have several serious limitations

Lack of mobility: directed infrared wireless systems use a line of sight principle, which makes it difficult for users because the alignment between the emitter and the detector would have to be continually adjusted.

Range: limited range of coverage. Directed infrared systems required line of sight and cannot have anything place in-between the infrared beam, which means they need to place close together to ensure that nothing obstructs there path, due to the angle of deflection, diffused infrared can cover a ranged of 50feet(15m), and because diffused infrared requires  a reflection point, it can only be used indoors.

Speed: limitation of speed, diffused infrared can send data a maximum speeds of only 4Mbps. This is because of the wide angles of the beam lose energy as it reflects. The loss of energy results in a weakening of the signal. The weak signal cannot be transmitted over long distance, nor does it have sufficient energy to maintain a high transmission speed, resulting in a lower data rate.

Because of the limitation, infrared wireless systems are generally used in specialised applications, such as data transfers between computers, digital cameras, handheld data collection devices, PDAs, electronic books and other similar mobile devices.

Radio waves provide the most common and effective means of wireless communications today. Radio waves travel the space or air similar to that of  electromagnetic wave, electromagnetic waves that travel in this fashion is called radio wave(radiotelephony). When an electric current passes through wire, it creates a magnetic field in the space around the wire. As this magnetic field radiates, it creates radio waves. Radio waves like light and heat waves, are electromagnetic waves, they move outward , usually in all directions from the source.

Unlike infrared light and heat radio waves are free from some of there limitations, radio waves can travel great distances and penetrate most solid objects.

Analogue and digital data are transmitted over radio waves. An analogy signal is one in which the intensity of the waves( voltage or amplitude) varies and is broadcast continuously.

Digital signal consists of discrete or separate pulses, as opposed to an analogy signal, which continuous. A digital signal has numerous starts and stops throughout the signal.

To transmit a digital signal over an analog medium, it requires a device know as a modem(MOdulator/DEmodulator) is to be used. A modem takes the distinct digital signals from a computer and encodes them into continuous analog signal for transmission over analog phone lines. The process of encoding the digital signals(bits) onto an analog wave is called modulation. The modem at the receiving end of the connection then reversers the process by decoding the analog signal into its original digital signal

Wavelength: is the distance between any point in one wave cycle and the same point in the next cycle

Frequency: is the number of time a cycle( which composed of one top (positive) and one bottom(negative peak) occurs within one second.  Frequencies are measured by the amount of cycles per second. The term hertz(Hz) is used instead of cycles per second.

Radio transmitter send what is know as a carrier signal. This is a continuous wave(CW) of constant amplitude(measured in volts) and frequency. The up and down movement of the  wave is call an oscillation signal or sine wave.

A CW by itself carries no useful information. Only after it is modulated does it contain some kind of information which is then called a carrier signal or carrier wave.

J. L. Olenewa (2014). Guide to Wireless Communications, ( Third Edition). Boston:CENGAGE Learning