2.5 IP Addressing

IP Address

32 bits into 4 groups, unique to every device, ensure there's no duplicates when you're assigning

Subnet mask

Usually 255.255.255.0; assigned by network administrator. Separates IP address into a network address (to identify which network it belongs to) and a host (the device) address.

- Works by setting all host bits to 0 and all network bits to 1s.

Default gateway

IP address for a router (forwards data from a local network to another network and vice versa).

DHCP Process

DORA

1. Device locates a DHCP server on local network

2. DHCP server offers IP address to device

3. Device requests IP address chosen from its offers

4. DHCP acknowledges request and assigns the IP address

Dynamic IP address

Network automatically reassigns IP addresses every time a device connects to a network.

Static IP address

IP address stays the same every time you connect to the network. To get this you can either:

1. disable DHCP and manually configure the network (hard/time-consuming)

2. configure an IP reservation for that device (easier and preferred)

APIPA (Automatic Private IP Addressing)

- an APIPA addressed is assigned when a device that NEEDS an IP address connects to a network that doesn't have a DHCP server

- APIPA devices can only communicate on a local network, NOT to outside networks

Class A range

0-127 (remember 127) - private range: 10

Class B range

128-191 (remember 191) - private range: 172

Class C range

192-223 (remember 223) - private range: 192

APIPA

169 ;) (remember 169) - private range: 169 (because APIPA IS private)

Public IP Addresses

IP addresses for devices that need the internet.

Private IP Addresses

IP addresses on devices that don't access the internet, they're only used privately on a singular network.