Networking 101

netw1

Network Terminology

In progress June 24, 2024

Why is a Network imporant??

  • A network is created when you think of anything interconnected. In the digital world we live in today, its any device connected to the same internet connection. Its important to know sharing a connection is a lot more significant than the words: internet connection.

  • Most importantly Networks allow sharing of much more than you anticpate.

What is a “Network”?

  • A network is a group of interconnected devices (all on the same Wi-Fi network) that can exchange data and resources together. Most notably, they share an internet connection. A simple home network with common household items such as smartphones, laptops, printers, smart devices, TV’s and other devices is considered a network.

Common Network infrastructure devices

  • ISP modem: ISP modem, allows access to the WorldWideWeb/Internet via DSL

  • Router: Distributes internet connections to devices through the Modem, then creates a local network (Wi-fi) when a router is connected

  • Access point: Extends a local network wirelessly.

  • Switch Extends the amount of wired connections.

Firewalls

  • a Firewall allows or denies traffic based on the rules that are set up. Common fields will include; Name, Description, Interface, Allow/Deny, Source IP/group, Destination IP/Group, Ports, and block all, whitelists, blacklists.

  • Many types of firewalls are implemented. Here is a short list of some examples:
  • a WAF (web application firewall), protects web-based applications
  • a Cloud Firewall, protects data transfer in cloud enviroments

  • multiple firewalls can be used in conjunction to more efficently route data, as well as having a layered network management.

  • what do Firewall rules look like? -Typically, firewall rules are very complicated. They require prior knowledge of the existing firewall rules.

PowerShell Ex:

FirewallRule1 -DisplayName “Allow HTTPS” - Direction Inbound -Protocol -TCP -LocalPort 80 -Action Allow FirewallRule2 -DisplayName “Block All others” - Direction Any -Protocol -Any -LocalPort Any -Action Block

Why is seperating devices so important?

  • Not all devices should have the ability to reach a Domain Controller or a Medical Device or a Manufacturing Sensor.

  • Often it does not make sense to allow devices to talk back and forth with every other device around it, often is it the case that it will technically create a larger and larger network until it is too big to manage. in other words it creates a larger attack surface or widens the network too much.

  • Not all access points can reach the same infrastructure as other APs, so it is impossible to have a large area or WAN on the same network. Although most of the time they share the same necessary infrastructure to provide internet access.

  • When we look at at the reason for a subnet, partially it is to divide a network into smaller, more efficient networks.

  • Another reason could be to seperate physical areas and regions such as a engineering department, sales group, 1st, 2nd, 3rd floor, and so on.

Guest Network

  • a Guest Network will be a seperate network that is only for visitors. for every reason

VLAN

  • a VLAN stands for Virtual Local Area Network. This is a logical segmentation configured on a network switch. This is commonly used for seperating different areas of business such as IT and HR for a company or different departments like a surgical ward and medical offices in a hospital

DMZ

  • a DMZ or de-militarized zone, is a subnet or sub-network that seperates a LAN Local area network, from untrusted networks or devices.

  • Usually a DMZ will face outwards, protecting the business enviroment and internal LANs.

  • Firewalls are a major part of network security, any application or user will have to be compliant to the firewall in order to reach outbound to the World Wide Web/Internet.

  • Standard abilities of a firewall will monitor and control network traffic.

  • Packet filtering for individual packets, stateful inspection of packets(Comparing previously passed packets),

  • NGFW(Next Gen Firewalls) Provide