Networking in Sec

Aduda Shem

• 2 min read
Networking in Sec
Networking

IP Addresses

The command ifconfig on Linux displays an inet — IPV4 address(in decimal notation) & inet6 — IPV6 address(in hexadecimal notation). IP address is essential in communication. (We communicate over layer 3)

2 ^ 32 = 4,294,967,296 → The possible number of IPV4 address we can have

2 ^ 128 = 3.402823669×1⁰³⁸ → The possible number of IPV6 address we can have

We still use IPV4 even after exhausting the possible addresses due to the presence of NAT-Network address Translation which allows assigning of Private IP addresses that passes through the Public IP addresses

IPV4 classes

MAC Address

MAC — Media access control /Physical address that allows us to communicate when using switches. It is a layer 2.

They have identifiers, take the first 3 pair of two out of the 6 pair of the mac addrress and paste it https://aruljohn.com/mac.pl to see the vendor(Company).

TCP, UDP, and The three-way-handshake

This is layer 4.

TCP — Transmission Control Protocol ,connection oriented protocol

UDP — User Datagram protocol , connectioneless protocol

TCP works in a three way handshake ;

SYN > SYN ACK > ACK.

Wireshark

A way to capture traffic from the internet is using wireshark.

Common Ports & Protocols

The OSI Model

  1. Physical layer— data cables, cat6
  2. Data layer — Switching, MAC addresses
  3. Network layer — IP addresses, routing
  4. Transport layer — TCP/UDP
  5. Session layer— Session management
  6. Presentation layer — JPEG, MOV, WMV
  7. Application layer — HTTP, SMTP