During the second week:
We continue discussing the Rules of Engagement
- We review the importance of Networking Infrastructure
- We discuss Google Hacking – How to Customize Google Searches to Get Better Results
- For those black box engagements, the client’s not providing the information.
Based on this week’s readings:
a. One key point you took from each assigned reading. (One or two sentences per reading)
b. One question that you would ask your fellow classmates that facilitates discussion.
1. Key Takeaways from readings
a. Basics of Computer Networking
i. Two useful commands for finding information of a server are ipconfig and nslookup. With the ipconfig command, you can find the IP address of a given device and adding “/all” to it will provide MAC address information. The nslookup command is useful in finding information on a given DNS server such as the name and other associated addresses.
b. Introduction to basic Networking terminology
i. While I knew about VPNs, I have not heard the term SAN. This stands for Storage Area Network and is used to connect systems to high-capacity storage devices.
c. TCP/IP Model
i. While the OSI model is present with its 7 layers, an alternative is the TCP/IP model, which uses 4 layers. These layers from top to bottom are the Application layer, Transport layer, Internet layer, and Network Access layer.
d. Layers of the OSI model
i. Like mentioned previously in contrast to the TCP/IP model, the OSI model uses 7 layers. From top to bottom: Application, Presentation, Session, Transport, Network, Data Link, and Physical. Because of how late this model was created, the internet relies on the TCP/IP model.
2. One question to ask classmates
a. While these readings provided rudimentary explanations of these concepts, are there any particular concepts that you learned about that you never heard of prior to this course?
1. Basics of Network Computing:
– The article covers the different network topologies, commands to get the hostname of your machine, the differences between IP addresses and MAC address, differences in ports, what the purpose of the netstat -a command is and the concepts of ARP and RARP. I wasn’t too familiar with RARP and the article helped clear up that it has been phased out since DHCP became more prevalent.
2. Introduction to basic networking terminology:
– This article went over the basic protocols like IP, FTP, SMTP and HTTP. It also explained what a storage area network is and what a VPN is. It explains how protocols are really just a set of rules that are followed by connected devices on a network to share information.
3. TCP/IP Model
– This article compares the TCP/IP model and the OSI model. It states TCP/IP is more reliable, contains less layers and takes advantage of both the presentation and application layers. OSI has 7 layers and is less reliable.
4. Layers of the OSI model
– This article broke down the layers of the OSI model. It explained that the transport layer is the heart of the OSI model, as it is responsible for the end to end delivery of the message – as stated in the article.
Discussion Question:
– In what special cases would you prefer a TCP/IP model over an OSI model
Basics of Computer Networking
This article helped me understand many common network acronyms and how they are related to each other. I specifically enjoyed reviewing the different unique identifiers of a network and how information is able to be sent to a specific location.
Introduction to Basic Networking Terminology
A key takeaway is how a host can act as a client when requesting information and a server when providing information. This duality and constant flow of information could lead to potential vulnerabilities if the right firewalls are not in place.
TCP/IP Model
I was unaware of this model and I learned its 4 layer structure of Application Layer, Transport Layer, Internet Layer, and Network Access Layer. It is more concise, more reliable, and less strict than the OSI model.
Layers of OSI Model
I was able to review the 7 layers of the OSI model: Application Layer, Presentation Layer, Session Layer, Transport Layer, Network Layer, Data Link Layer, and Physical Layer. This is a widely used reference model that specifies standards for communications protocols and the functionalities of each layer. (Basics of Computer Networking)
Discussion Question
Have you worked closely with either reference model mentioned? What are the pros/cons to using either one?
Basics of Computer Networking:
While I was already familiar with much of this information, I had never heard of the network topologies before. I was also not familiar with the concept of RARP being the foundation for DHCP.
Introduction to basic networking terminology:
I think most interestingly the article mentions the concept of a peer being a host that requests and sends information. Peer-to-peer (P2P) is becoming a prevalent concept as of late in things like cryptocurrencies and the decentralized internet.
TCP/IP model:
The two most interesting pieces of information regarding the TCP/IP model in my opinion are that the transport layer does not provide ensured packet delivery unlike the OSI model, and that the network layer only provides connectionless services (also unlike the OSI model).
OSI Model:
There are times where I hear Layer 2 or layer 3 devices mentioned. Prior to this reading I was not entirely sure what that pertained to or meant. It was also interesting to see that the Transport Layer, layer 4/heart of the OSI model, is where error control by essentially correcting frames occurs.
Discussion Question:
Do you think that the OSI model should still be used? In some cases it is being replaced slowly by a modified OSI-cl0ud hybrid model that is geared more towards a cloud-based infrastructure across society at large..
1. Basics of Network Computing:
– Network infrastructure is key to protecting/penetrating data in transit. This article explained the differences between DHCP vs static IP, and the vulnerabilities of each.
2. Introduction to basic networking terminology:
– This article explained commonly used protocols like TCP/IP, FTP, SMTP and HTTP. Industry standards are vital to enabling different platforms and clients to communicate with each other.
3. TCP/IP Model
– This article compares the TCP/IP model and the OSI model. The TCP/IP has 4 layers, while the OSI model has 7. TCP/IP offers reliability over unreliable networks.
4. Layers of the OSI model
– The OSI Model is a logical and conceptual model that defines network communication used by systems open to interconnection and communication with other systems. The 7 layers are Application, Presentation, Session, Transport, Network, Data Link, and Physical.
Discussion Question:
–The OSI model was created in the early 1980’s, and on one hand it is impressive that it is still in use and able to support modern use, but on the other hand, what vulnerabilities are present?
One key takeaway that I took away from each reading :
Basics of Computer Networking
Basic network infrastructure, and how they are set up.
Introduction to Basic Network Terminology
Network standards and simple commands
TCP/IP Model
Introduction to the TCP Model, and its layers and functions
Layers of the OSI Model
Functions and layers of the OSI model
One question that I think would facilitate discussion would be : Why do you think the OSI Model is only a logical/conceptual model, and not implemented?