CST3607 Class Notes 2022-02-03

News and Tools

Hundreds of Subway Riders Evacuated After Power Surge Shut Down Service On Eight Lines

  • Even though there are two emergency generators designed to automatically replace the battery power in cases of power outages, the generators failed to turn on
  • And the MTA’s alert system failed to send alerts the back-up generators weren’t working

SolarWinds Hack!!!! (A must know)

M.E.Doc Backdoor & Maersk NotPetya Recovery

Prepare for Shipping Delays and Price Hikes

Other news

Identity Theft is a big problem.

Password Managers

Protecting Your Accounts and Identity from Theft

  • Slides and notes from the presentation I did at WordCamp NYC

Resume Privacy

  • If you’re going to post, or have posted, your resume on-line, that is publicly accessible, make sure to edit it to remove your address and phone number.
  • Your address should be remove from your resume, even if you’re not posting it publicly.

Credit Freezes Are Now Fee-Free

Two Factor Authentication (2FA) / Multi-factor Authentication (MFA)

Best Practices

  • 4 things you should be doing right now so you won’t get hacked
    1. Use passwords with at least 14 characters that can’t be found in the dictionary.
    2. Use a password manager so you won’t have to remember all of them.
    3. Turn on two-factor authentication and your account will remain secure even if your password is hacked. Unless your phone has been SIM-jacked.
    4. Be especially wary of e-mails asking you to do something, or phone calls about the security of your accounts.
  • Network Best Practices

Disable UPnP (Universal Plug-and-Play) on Your Network

Protocol Review:

  • DHCP (Dynamic Host Configuration Protocol)
  • DNS (Domain Name System) (or Service or Server)
  • NAT (Network Address Translation)
    • Network Address Translation is an Internet Engineering Task Force (IETF) standard used to allow multiple PCs or devices on a local area network to share a single, globally routable IP address.
    • NAT is also used to avoid address renumbering in a LAN when topology outside the private network changes.
  • ARP (Address Resolution Protocol)

Protocol & Standards you should be familiar with:

What is a network?

  • LAN (internal, private) vs WAN (external, public)

Cisco’s Three-Layer Hierarchical Model

  • Core layer or Backbone
  • Distribution layer
  • Access layer

Types of Ethernet cabling

Ethernet cable types for different devices.
Ethernet cable types for different devices

Straight-through cables are used to connect unlike devices.

  • e.g. Host to Switch, Router to Switch
  • On a host: Pins 1 & 2 are transmit, and 3 & 6 are receive.

Crossover cables are used to connect like devices.

  • e.g. Switch to switch, Router to host, Router to Router
  • It is possible to connect switches using a straight-through cable because many switches have auto configuring ports.  Usually referred to as Auto-MDIX. a.k.a. Auto Uplink.

Roll-over cables are used to connect a hosts’ RS-232 / EIA-TIA-232 serial interface to a routers console port.

  • The default COM port settings for Cisco routers & switches are:
    • Bits per Second: 9600, Data bits: 8, Parity: None, Stop Bits: 1, Flow Control: None

Unicast, Broadcast, Multicast

The Internet Protocol and other network addressing systems recognize three main addressing methodologies:

  • Unicast addressing uses a one-to-one association between the destination address and the network endpoint: each destination address uniquely identifies a single receiver endpoint.
  • Broadcast addressing uses a one-to-many association, datagrams are routed from a single sender to all endpoints, in the broadcast domain, simultaneously in a single transmission. The network automatically replicates datagrams as needed for all network segments (links) that contain an eligible receiver.
  • Multicast addressing is the sending of the same message simultaneously to to multiple endpoints simultaneously in a single transmission, but not to all. The network automatically replicates datagrams as needed for all network segments (links) that contain an eligible receiver.

Collision and Broadcast Domains

Telemetry, Logging, Monitoring

Telemetry is an automated communications process by which measurements and other data are collected at remote or inaccessible points and transmitted to receiving equipment for monitoring.

Monitoring & Logging

  • syslog and SNMP are common tools used to monitor systems.
  • Syslog (System Logging Protocol) [RFC 5424] is a standard protocol used to send system log or event messages to a syslog server. It is primarily used to collect various device logs from several different machines in a central location for monitoring and review.

Read / Watch

CCNA Certification Study Guide, Volume 2: Exam 200-301

  • Read Chapter 2: TCP/IP
  • Do the Written Labs
  • Answer the Review Questions
    • Do not submit your answers for this chapter. The answers are in the Appendix

Subnetting Tutorial & Reference Page


Check if your router has UPnP, or any other ports/protocols, exposed to the Internet

  • Go to GRC.com > Services Menu > ShieldsUP!
  • Run GRC’s Instant UPnP Exposure Test
  • Run GRC’s “All Service Ports Test
  • Report your results at our next class:
    • Was UPnP exposed to the public?
    • Did you find any open ports?
    • Did you find any closed ports?
    • Were all port stealth?