CST3607 Class Notes 2018-08-30

News

More than 150,000 Internet-facing printers were scanned, located, and used

  • If your router has UPnP enabled, your printers, (or anything else on your network), may have punched a hole through your border router’s stateful NAT firewall to make itself “available” to anyone on the public Internet in the world.

Tools and News

Identity Theft is a big problem.

Protocol Review:

  • DNS (Domain Name System) (or Service or Server)
  • DHCP (Dynamic Host Configuration Protocol)
  • 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)

Cisco IOS and Router Command Reference

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 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.

How would you know that a network has been compromised?

Network Analyzer/Packet Sniffer

Segment Your Network / Isolate Guests & IoT devices from your main segment

Ubiquiti Networks EdgeRouter X:

Universal Plug-and-Play (UPnP)

Microsoft OneNote

Cisco Learning Network

  • Get access to the Packet Tracer router simulator
  • Free learning resources
  • Cisco certification exam topics
  • CCNA, CCNP study groups
  • Sample CCENT, CCNA, CCNP study questions
  • Career resources
  • IT learning games
  • Community manager support
  • Social learning with IT experts
  • Cisco Exam Preparation – Studying for Results

Read

Do

  • CCNA R&S Study Guide 2nd Edition: Chapter 2: Written Labs & Review Questions
  • Until further notice, bring in a stand-alone calculator, (not one on your phone, or computer), to every class. The calculator must have an Exponent function (^key) ( x)
  • Sign up for a free Cisco Learning Network account. [A paid membership is not necessary to access a lot of the material]
  • 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

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