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    HistoryEdited Sep 17, 2019 5:04 PM by admin…

    fsck, IPNetMonitor 2.7.3

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    1. fsck -yf upon single user start (command-s)
    2. open IP net monitor (blue guy icon)
    3. Task bar:

    1. address scan: try 10.14.4.0/24, 10.14.6.0/24 or 10.14.252.0/24 (10 means HPA, 14 means elab, 252 means leased/borrowed address, 0 means whole network, 24 means the last numbers can change between 1-254.
    2. connections: open, then open a browser, note the connections you see. Browsers are BUSY
    3. DHCP lease: release and rebind, note your address, and how long you can keep it
    4. DNS lookup (except for the dark web) this is the internet phone book, translating names like physics.hpa.edu into numbers like 10.14.250.2. Try resolving names into numbers and then plug these into your browser
    5. Interface info: make sure to note the MAC address of your computer, compare with others-what is similar, what is different?
    6. Link Rate: try this to different servers, like physics.hpa.edu. This tells the link speed between you and the machine, which depends on your connection, your computer, and the server (also anything in between). On a mac, you can also hold the option key while clicking on the little fan icon, it should show you other stuff. Note also that a bit is one piece of information, 8 bits make a byte. mb is megabits, mB is megabytes.
    7. Monitor lets you watch the traffic in and out of your wireless or wired connection, note the green (in) vs. red (out) while you browse the web or watch a youtube video. Note also that when you are using TCP to look at a web page, there is a constant dialog between you and the server (two way connection), while youtube and other streaming services use UDP, which does not care if you get the information or not. You may also tie this into why sharing apps like bit torrent or utorrent slow an entire network down: they slow down the outbound traffic.
    8. Ping is the same as what you used from terminal, note the return speed, consistency, and what interface you choose.
    9. Port scan is like knocking on all the doors on a house. Try it on one of the Pi units (10.14.88.2) then on the physics server (10.14.250.2). Note which ports show up, like ssh (22) http (80) and others.
    10. Next: server scan, TCP dump and traceroute