IT Knowledge
Networking
How devices find each other, talk and stay safe.
01
What is a network?Two or more devices connected so they can share data. The internet is just a network of networks.
3 min read
02
The OSI modelA seven-layer map of how data travels. Each layer does one job and only talks to the layers next to it.
4 min read
03
The TCP/IP modelThe practical four-layer model the internet is built on.
3 min read
04
IP addressesThe postal address of a device on a network, so packets know where to go.
4 min read
05
Subnetting and CIDRSplitting one network into smaller ones. The mask tells which part of the address is the network and which part is the host.
5 min read
06
MAC addresses and ARPIP says where a device is on the map; the MAC address is the name on its network card. ARP connects the two.
3 min read
07
DNSThe phone book of the internet: it turns names like rahimly.com into IP addresses.
4 min read
08
DHCPThe service that gives your device an IP address automatically the moment you join a network.
3 min read
09
TCP, UDP and portsIP brings data to the right computer; the port brings it to the right program.
4 min read
10
PingThe simplest network test: send a tiny packet, wait for the echo, measure the round trip.
3 min read
11
Switch vs routerBoth move traffic, but at different levels: a switch inside one network, a router between networks.
3 min read
12
NATThe trick that lets a whole home share one public IP address.
3 min read
13
VLANsOne physical switch, several separate networks. Like building walls inside one room.
3 min read
14
HTTP, HTTPS and TLSHTTP is how browsers ask for pages. HTTPS is the same thing inside an encrypted TLS tunnel.
4 min read
15
Wi-FiA network over radio waves, defined by the IEEE 802.11 standards.
3 min read
16
FirewallsThe bouncer at the door: it checks traffic against rules and decides what gets in and out.
3 min read