IP Addresses

Take the following IP address for example: 192.168.107.25/16 Answer the following: • What is the network portion of the address? • What is the host portion of the address? • What is subnet mask? • How many bits are available to use to define both portions of the address?

Network portion: 192.168.0.0 Host portion: xx.xx.107.25 Subnet mask: 255.255.0.0 There are 16 usable bits assigned to either portion.

What is the following subnet mask in CIDR notation? Why? 255.255.255.0

/24 255 = 1111 1111 8*3 = 24

What is the following subnet mask in CIDR notation? Why? 255.255.255.192

/26 255 = 1111 1111 8*3 = 24 192 = 1100 0000 24 + 2 = 26

What is an important number in the loopback range?

127.0.0.1

How many bits are in an IPv6 address?

128

Given the IP address of 192.168.107.25 And the subnet mask of 255.255.255.0 Determine the "network" portion of the address and the "host" portion.

192.168.101.15 = 1100 000 . 1010 1000 . 0110 0101 . 0000 1111 255.255.255.0 = 1111 1111 . 1111 1111 . 1111 1111 . 0000 0000 Network portion: 192.168.107.0 Host portion: xx.xx.xx.15

How many bits are in an IPv4 address?

32

What is a subnet?

A range of IP addresses in which all devices in the range can communicate directly with each other, no router required.

What is an IP address?

A unique numerical address under the Internet protocol, assigned to each device in a network so network components can appropriately identify each other on a network.

How can you tell if a device is on the same subnet?

By looking at the network portion of its IP address.

What is CIDR notation, and what is it for?

Classless Inter-Domain Routing: it is used to compactly represent IP addresses (and their associated network masks)

What is 127.0.0.0/8 ranged called?

The "loopback" range.

What is the loopback range managed by?

The OS.

What must happen when a device on one subnet wants to send a packet to another device that is NOT on the same subnet?

The device must send the packet through a router: this router must ALSO be on the same subnet.

What are IP addresses in the loopback range used for?

These addresses are used by the host to address itself. This also called the "localhost".