Let’s learn about technologies used to extend our network to the Internet and how it works in today’s #FromZeroToHacker lesson.
| Table of contents |
| Introduction |
| What I have learnt today? |
| Stats |
| Resources |
Introduction
Controlling your network is very important.
Basic stuff such as Firewalls that control what traffic enters and exits to VPN, LAN networking devices and more, is important to know as a bad configuration can lead to attack vectors that may harm our connections and computers.
What I have learnt today?
Intro to Port Forwarding?
Port forwarding is an essential component in connecting devices over the internet.
In this network, there is a web server on port 80, with only the other 2 computers having access to it.
If we want to be accessible to the public (over the Internet), we need to implement port forwarding:
Port forwarding just opens specific ports, and it is configured at the router of a network.
Firewalls 101
A firewall is a device (or software) responsible for determining what traffic is and isn’t allowed to enter and exit. We can configure a firewall to permit or deny traffic from entering or exiting a network base on factors such as:
- Where the traffic is coming from?
- Where is the traffic going?
- What port is the traffic for?
- What protocol is the traffic using (TCP, UDP, or both?)
Firewall can be Stateful or Stateless:
- Stateful: Permits or denies traffic depending on the entire connection rather than inspecting individual packets. It consumes more resources compared to stateless firewalls. Also, if a connection is broken, it will block the entire device.
- Stateless: This firewall checks individual packets rather than an entire connection, using then, less resources, as it is based purely on a set of rules that we defined within the firewall. This kind of firewall is great when receiving large amounts of traffic (such as a DDOS attack)
VPN
A Virtual Private Network (or VPN) allows devices on separate networks to communicate securely by creating a dedicated path between each other (a Tunnel).
For example, we have a network where only devices within the same network can communicate. If we want to work remotely, we need to connect to that network. We can do so with a VPN:
While each device is still part of Network #1 and Network #2, they are together in a private network (Network #3) that only devices connected to this VPN can communicate.
This allows networks in different physical locations to be connected together, and offers privacy (data is encrypted) and anonymity (An ISP can view your traffic and you can be tracked easily).
LAN Networking devices
What is a router?
A router connects networks and passes data between them by the process of routing (hence the name). In Routing, the router looks for the most optical path (layer 3 from the OSI model) between devices:
Different protocols will decide which path is better based on what path is the shortest, most reliable, and has the faster physical medium.
What is a switch?
A switch is a device responsible for providing a means of connection to multiple devices using Ethernet cables:
Switches operate at both layer 2 (Data Link) and layer 3 (Networking) of the OSI model. They send forward frames (packets with the IP stripped are called frames) to the correct device.
A technology called VLAN (Virtual Local Area Network) allows specific devices within a network to be virtually split up, so they both have access to the internet but are treated separately.
Stats
From312.278th to 295.688th. Let’s go!
Here is also the Skill Matrix:
