Know How...

Jan 11th 2018

Know How... 364

You Feeling Lucky?

NMAP, RasPi, Nerf, Lazer Tag, IR, and more...
New episodes every Thursday at 2:00pm Eastern / 11:00am Pacific / 19:00 UTC.
Category: Help & How To

Fr. Robert Ballecer and Patrick Delahanty show you how to can get information about all the devices on your network, how to turn a Raspberry Pi into a Wi-Fi router, solving filament problems in a 3D printer, and modifying Nerf and Lazer Tag guns. 

Nmap Me

"I started a search for a software interrogation program to show all the information about the devices on my network. My search returned some results. But my nerve ending stood on high alert as I started reading about the options within some software available. I was turned off by Wireshark and its complexity. (No disrespect intended to the Wireshark community) Decided a better road traveled would be asking; Has anyone had any experience with this type software and the trust level(from usage)?" - Rud Dog

Fing (Android & iOS)

  • Basic Networking Mapping
  • Can do pings & traceroute

NMAP (Windows, macOS, Linux)

  • nmap is an open source network tool/port scanner that can scan everything from a large network to a single host
  • It uses raw IP packets to let us know what hosts are available on a network, what ports they have open, what OS they are running and dozens of other parameters available to those who are willing to dive into the network protocols.

Quick Notes:

Basic Commands

  1. When you install NMAP on Windows, its going to install "WinPcap" service (Windows Packet Capture) service -- Allow the install and let it run on startup.
  2. I'm running all these commands in a shell that has root
  3. There's a GUI, but I prefer the command line
    1. Discover all IPs in a subnet
      • "nmap -sP x.x.x.x/y" (This is a "ping scan")
      • Where 'x.x.x.x' is the IPv4 address of the subnet you want to scan
      • Where 'y' is the size of your address space
      • For example: If I use "ipconfig /all" to determine that I have an address of 192.168.0.76 and a mask of 255.255.255.0
      • I know my subnet is 192.168.0.0
      • My subnet size is /24
      • so I would use the command "nmap -sP 192.168.0.0/24"
      • You can also use wildcards and ranges (Ex: "nmap 192.168.1.1-50" or "nmap 192.168.1.*")
      • This tells nmap to send a icmp echo request to ports 443, and 80 to all addresses within the specified subnet.
      • This only gives us a list of devices that respond to that request
      • NOTE: Just because a device doesn't respond, that doesn't mean it's not there.
    2. Identify Hostnames
      • "nmap -sL x.x.x.x/y"
      • This will send a packet to all the hosts in the range and return their reported network names
    3. Identify the Operating System
      • "nmap -O x.x.x.x"
      • This will attempt to identify the OS of the host
    4. Scanning for Open Ports on a specific host
      • "nmap x.x.x.x"
      • This will look at a specific host and tell you what ports are open on that host
    5. Show Host Interface and Routes
      • "nmap --iflist"
    6. Verbose!
      • Add "-v" to find out what's happening
    7. Saving your scan to a text file
      • "nmap 'whatever you choose to do' > output.txt

RasPi WiFi Router

"I've made a recent post about using a raspberry pi as a tor box and I figured that I don't need the tor part. So does anyone know how to turn a raspberry pi into a WiFi router on raspbian. Any support will be great!!" - Michael

Turning a Raspberry Pi into a Wireless AP

  1. Image Raspbian onto your SD card
  2. Expand the volume
    • Open Terminal
    • "sudo raspi-config"
    • Select option 7
    • Select A1
  3. Change the default password
    • Select option 1
    • RasPi will reboot
  4. Turn your RasPi into an Access Point
    • A GIT user by the name of "Harry Allerston" created a script to automate the process
    • Open Terminal
    • "git clone https://github.com/unixabg/RPI-Wireless-Hotspot.git"
    • "cd RPI-Wireless-Hotspot"
    • "sudo ./install"
    • "Y" to agree to terms
    • "Y" to use preconfigured DNS
    • "Y" to use Unblock-Us DNS servers
    • "N" for WiFi defaults
    • Type in a new WiFi password (it will be checked)
    • Type in a new SSID
    • Type in your desired WiFi channel (1, 6, 11)
    • Type "N" when asked - "Are you using a rtl871x chipset?"
    • Type "N" for Chromecast support (unless you plan to use a Chromecast w/RasTor)
    • Your Pi will reboot
  5. Update your Raspbian installation
    • Open Terminal
    • "sudo apt-get update"
    • "apt-get" is a diagnostic tool that updates all packages and checks for broken dependencies

    Filament Problems

    "So i got my monoprice maker select plus, and did a print with the filament that came with it, but I'm having trouble with the hatchbox filament i got. I started a print, left, and when I came back, no print was on the build plate. I checked for jams and noticed a worn spot on the side of the filament. It looked like the wheel was trying to push filament thru the hot end but it wasn't going. Thanks for any tips" - Heath Reeder

    • This is most likely a hot-end problem. (Not enough heat)
    • You can increase the hot-end temp (default is 200... better is 210) in your slicer or on the printer.

    Lazer Tag Guns!

    The Worlds of Wonder Lazer Tag equipment uses a 57.6 kHz carrier frequency modulated with a 1.8 kHz signal.

    The frequency for Tiger Electronics Lazer Tag equipment is 30 KHz +/- 10%, modulated as three 25-millisecond IR bursts separated by 50-millisecond idle periods for normal tags, and separated by 100-millisecond idle periods for super-strike tags. Some details are available in US Patent #5,904,621.

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