2.5 - IPv4 and IPv6, Assigning IP addresses

Question 1

IP addressing

Answer 1

IPv4 = primary protocol for everything we do

IPv6 = now part of all OS’s
-backbone of internet infrastructure

Question 2

IPv4

Answer 2

Internet protocol version 4
-OSI layer 3 address

Question 3

IPv6 addresses

Answer 3

Internet protocol v6 - 128 bit address
-340 undecillion

Question 4

Networking with IPv4

Answer 4

IP address
-every device needs unique IP address

Subnet mask
-used by local device to determine its subnet
-subnet mask isn’t usually transmitted across the network

Default gateway
-router that lets you communicate outside of your local subnet
-default gateway must be IP address on the local subnet

Question 5

DNS servers

Answer 5

We remember names

Internet routers only know IP addresses

Domain name services translate between names and IPs

You configure TWO DNS servers in your IP config b/c of how important it is!

Question 6

DHCP Process (DORA)

Answer 6

1. Discover
   -client to DHCP server
   -find all available DHCP servers
2. Offer
   -DHCP server to client
   -send some IP address options to client
3. Request
   -client to DHCP server
   -client chooses offer + makes formal request
4. Acknowledgment
   -DHCP server to client
   -DHCP server sends acknowledgment to client

Question 7

DHCP

Answer 7

IPv4 config used to be manual

BOOTP (bootstrap protocol) 1993
-some manual configs were still required
-didn’t know when IP address might be available again

DHCP (dynamic host configuration protocol)
-1997
-provides automatic IP address/IP config for almost all devices

Question 8

Turning dynamic into static (assigning IP addresses)

Answer 8

DHCP assigns IP from 1st available one in a pool of addresses
-IP occasionally changes

Might not want your IP to change
-server, printer, personal pref.

Disable DHCP on device
-config IP address info manually
-requires additional administration

Better: config IP reservation on DHCP server
-associate specific MAC address with an IP address

Question 9

Avoid manual configurations (assigning IP addresses)

Answer 9

No DHCP server reservation
-you manually configure IP address

Difficult to change later
-b/c must visit device again

DHCP reservation = preferable
-change IP address from DHCP server

Question 10

APIPA

Answer 10

Automatic private IP addressing

Link-local address - no forwarding address

IETF reserved 169.254.0.0 - 169.254.255.255
- first + last 256 addresses = reserved

Automatically assigned
-used ARP to confirm address isn’t in use