IP Addressing and Subnetting

Unicast IPv6

a unicast address specifies a single interface. Data packets sent to a unicast destination travel from the sending host to the destination host. It is a direct line of communication.

VLSM (Variable Length Subnet Mask)

allows subnets of different sizes to be created from the same network address basically subnetting subnets

EUI64

auto configuration for IPv6 to assign IPv6 addresses across the network using its own host ID based on a MAC address

Multicast addresses (IPv6 type address)

begins with FF

IPv6 address structure

hexadecimal digits is 4 bits 128-bits in an IPv6 address No more than 32 hexadecimal digits 16 bits between each colon 2018:0:0:0000:0:000:4815:54ae consecutive groups of 0's can be summarized as :: 2018::4815:54ae

127.0.0.1

loopback address

purpose of subnets

more efficient use of IP addresses than classful defaults enables separation of networks for security enables bandwidth control

Class C

192-223 255.255.255.0 CIDR notation: /24

How many assignable IP addresses exist in the 172.16.1.10/27 network? a. 30 b. 32 c. 14 d. 64

/27 11111111.11111111.11111111.11100000 3 borrowed bits and 5 host bits 2^5= 32 32 - 2 = 30 a. 30

How many assignable IP addresses exist in the 172.16.1.10/28 network? a. 16 b. 14 c. 18 d. 32

/28 11111111.11111111.11111111.11110000 4 borrowed bits and 4 host bits 2^4 = 16 16-2 = 14 b. 14

Subnetting exam tip (subnetting chart)

/30 = 64 subnets, 4 IPs /29 = 32 subnets, 8 IPs /28 = 16 subnets, 16 IPs /27 = 8 subnets, 32 IPs /26 = 4 subnets, 64 IPs /25 = 2 subnets, 128 IPs /24 = 1 subnet, 256 IPs the bigger the CIDR notation, the higher the subnet and lower the IP

Classful subnet

/8 , /16, /24

converting binary to decimal

128 64 32 16 8 4 2 1 1 1 1 1 1 1 1 1 Convert 10010110 into decimal format 128 0 0 16 0 4 2 0 128 + 16 + 4 + 2 = 150

Convert 10010100 into decimal

128 64 32 16 8 4 2 1 128 + 16 + 4 = 148

Convert 49 to binary

128 64 32 16 8 4 2 1 32 + 16 + 1 = 49 0 0 1 1 0 0 0 1

Convert 01101011 into decimal

128 64 32 16 8 4 2 1 64 + 32 + 8 + 2 + 1 = 107

Class B

128-191 255.255.0.0 cidr notation: /16

Convert 167 (decimal) into binary

167 1 0 1 0 0 1 1 1 128 +32 + 4 + 2 + 1

Class D

224-239 NA NA

IPv4 address

A 32-bit binary number assigned to a computer on a TCP /IP network. 4 separate numbers and divided by dots. 172.21.243.67

IPv6

A new protocol developed to replace IPv4, addressing the issue of IP address exhaustion. 128 bit address instead of 32 no broadcasts no fragmentation - performs MTU (maximum transmission units) discovery for each session can coexist with IPv4 simplified header - 5 fields instead of 12 fields

NDP (Neighbor Discovery Protocol)

A protocol that is part of the IPv6 protocol suite, used to discover and exchange information about devices on the same subnet (neighbors). In particular, it replaces the IPv4 ARP protocol.

CIDR (Classless Inter Domain Routing)

A subnetting method that selects a subnet mask that meets an individual network's networking and node requirements and then treats the mask like a 32-bit binary word. Classful CIDRs: /8, /16, /24 Classless CIDRs: any / from 1-32 not including /8, /16, /24

169.254.0.0 - 169.254.255.255

APIPA range of IP addresses. IP address' assigned when DHCP server is down.

Non-routable IPs

Also known as Private IP's

static IP address

An IP address that is manually assigned to a device and remains constant until it is manually changed. Simple, time consuming, prone to human errors, and impractical for large networks.

Multicast IPv6

As with IPv4 addresses, multicasting sends and receives data between groups of nodes. It sends IP messages to that group rather than to every node on the LAN (broadcast) or just one other node (unicast).

Globally routable unicast addresses (IPv6 type address)

Begins with 2000 to 3999

Link-local address (IPv6 type address)

Begins with FE80

The Host portion of the IP address

Binary 0 portion of address, Class A: 11111111.11111111.11111111.0

The Network portion of the IP address

Binary 1 portion of address, Class A: 11111111.1111111.11111111.0

Private IP ranges

Class A: 10.0.0.0 - 10.255.255.255 Class B: 172.16.0.0 - 172.31.255.255 Class C: 192.168.0.0 - 192.168.255.255

Assignable IP addresses by class

Class A: 16,777,214 2^24 -2 Class B: 65,534 2^16-2 Class C: 254 2^8-2 - 2 because must save IP for network ID and broadcast ID

How many hosts or usable IPs are in this subnet? 192.168.1.0 /24

Class C IP address, a classful subnet 11111111.11111111.11111111.00000000 24 network bits and 8 host bits 2^8 = 256 -2 = 254 hosts available or usable IPs

How many hosts or usable IPs are in this subnet? 192.168.1.0 /26

Class C IP address, a classless subnet 11111111.11111111.11111111.11000000 Borrowed 2 bits from the host portion of IP 26 network bits and 6 host bits 2^6 = 64 -2 = 62 hosts available or usable IPs

Anycast

Designed to let one host initiate the efficient updating of router tables for a group of hosts. IPv6 can determine which gateway host is closest and sends the packets to that host as though it were a unicast communication That host can anycast to another host in the group until all routing tables are updated, essentially like a broadcast. Simplified: anycast packet is sent to closest router to then push that anycast message to other hosts. Those hosts then push that anycast packet to routers close to them until all hosts have received the packet.

Class A

First octet value: 1-126 255.0.0.0 CIDR notation: /8

dynamic IP address

IP address statically assigned by DHCP server within an IP range. Quick, easier, less confusing, simplistic for large networks.

What does DHCP server give to a device?

IP address, Subnet Mask, Default gateway, DNS server Each IP address is given as a lease, once lease is up it is given back to the DHCP server.

default gateway

In a TCP/IP network, the nearest router to a particular host. This router's IP address is part of the necessary TCP/IP configuration for communicating with multiple networks using IP.

DNS

Port 53 Domain Name System Translates domain names into IP addresses

DHCP (Dynamic Host Configuration Protocol)

Port 67 and 68 A network service that provides automatic assignment of IP addresses and other TCP /IP configuration information.

Routable IP

Publically routable IP addresses are globally managed by ICANN (internet Corporation for Assigned Names and Numbers) Usually the type of IPs web servers have.

Calculating number of subnets from 192.168.1.0 /26

The normal classful address is 24, the CIDR notation for this IP is /26 so we borrowed 2 host bits. 2^2 = 4 the 4 means we will have 4 subnets. Remember in /26 we will have 64 IPs in each subent and 62 usable IPs because 64-2 = 62. What we do now is add 64 to each subnet to get the total amount of subnets in each IP, or just increment each IP by 64: 192.168.1.0 - 192.168.1.63 192.168.1.64 - 192.168.1.127 192.168.1.128 - 192.168.1.191 192.168.1.192 - 192.168.1.255

subnet mask

The value used in TCP/IP settings to divide the IP address of a host into its component parts: network ID and host ID.

Unicast (IPv4)

a form of message delivery in which a message is delivered to a single destination

Multicast (IPv4)

a form of transmission in which a message is delivered to a group of hosts

Zero Configuration (Zeroconf)

a standard developed by IEEE which recommends how to design a device that automatically detects other devices on the same network or on a nearby network segment without the need of intervention by an administrator or a DHCP or DNS server. Similar to APIPA, does not require DHCP or DNS to talk internally on the network. Uses SLP (service location protocol) port 427

broadcast (IPv4)

the data is sent to every host on the network.