Download IP Addressing Notes - Mr. Dixon`s Weebly

PC Maintenance and Repair - IP Addressing
1. What is an IP Address?
a. An IP address is what uniquely identifies you on a network or Internet.
b. No two computers can share the same IP address.
c. Telephone number analogy. If I dial a number, I connect with just one person.
d. All devices, whether computer, laptop or cell phone require an IP address to go onto the Internet.
2. What does an IP address look like?
a. Examples: 192.168.1.1 or 10.3.12.65
b. It is composed of 4 numbers separated by periods.
c. The range of values in each octet is from 0 to 255. Any other value is invalid.
d. Each octet is built from 8 binary digits (bits, 0 or 1)
3. What are the parts of an IP address?
a. Network
i. The first part of an IP address tells you which network you belong to.
ii. Devices on the same network can communicate without having to go on the Internet. (LAN)
iii. All IP addresses are registered so that there are no duplicate IP addresses assigned. (ARIN)
iv. Again, think telephone numbers. The network part of an IP address is like the area code.
v. The network part of an IP address always appears first.
vi. In order for two devices on the same LAN to communicate, they must have the same network part
to their IP address.
vii. For example, on our network, everyone's shares the first two octets 10.3. This is the network part of
all of our IP addresses here at East Kentwood High School.
b. Host
i. The second part of the IP address is used to uniquely identify you on our network.
ii. While all devices on the same LAN will share the same network address, they must all have different
host parts to their IP addresses. This is what allows them to be uniquely identified on the LAN.
iii. For example, on our EK network, we all share 10.3 in the first two octets, but our third and fourth
octets are all different. Mine is 10.3.12.65 and yours might be 10.3.13.182
4. What are the different classes (sizes) of IP addresses?
a. Class A
i. The first octet value will be in the range from 1 to 127
ii. Only the first octet is used for network. (same for all devices)
iii. Octets 2 through 4 are used for host. (N.H.H.H)
iv. This gives over 16 million different IP addresses for each class A network. (224)
v. Class A networks are typically only given to large companies, universities or ISPs.
vi. They are often broken up into smaller chunks to conserve IP addresses. (subnetting)
b. Class B
i. The first octet value will be in the range from 128 to 191
ii. The first and second octets are used for network. (same for all devices)
iii. Octets 3 and 4 are used for host. (N.N.H.H)
iv. This gives over 65 thousand different IP addresses for each class B network. (216)
c. Class C
i. The first octet value will be in the range from 192 to 223
ii. The first, second and third octets are used for network. (same for all devices)
iii. The fourth octet only is used for host. (N.N.N.H)
iv. This gives 256 different IP addresses for each class B network. (216)
v. Class C networks are usually reserved for smaller companies or schools.
5. IP Addressing Concepts
a. Subnet Mask
i. This is a 4 octet value that accompanies an IP address
ii. It tells which part of the IP address is network and which part is host.
iii. Network bits = 1; Host bits = 0
iv. Class A subnet mask - 255.0.0.0
v. Class B subnet mask = 255.255.0.0
vi. Class C subnet mask = 255.255.255.0
b. Default Gateway
i. This is the IP address assigned to the device that allows you to leave your LAN and connect to the
Internet.
ii. This device is usually a router.
iii. The default gateway is usually reserved the first usable IP address on your LAN.
c. DHCP - Dynamic Host Configuration Protocol
i. This is a way to automatically assign IP addresses to devices on the same network.
ii. It requires a dedicated DHCP server.
iii. The IP addresses are leased to the hosts on the network by the DHCP server.
iv. If the host goes inactive, the DHCP server will reclaim the IP address at the end of the lease and give
it to another host.
6. What are the three types of IP addresses?
a. Network Address
i. The first IP address on a network is called the network address.
ii. The host portions is filled up with all 0s (zeros).
iii. It is used to represent the entire network.
iv. It cannot be assigned to a device.
b. Broadcast Address
i. The last IP address on a network is called the broadcast address.
ii. The host portion is filled up with all 1s.
iii. It is used to send messages to all hosts on the network. (Broadcast)
iv. It cannot be assigned to a device.
c. Host Address
i. All of the IP addresses in between the network and broadcast addresses are host addresses.
ii. These can be assigned to devices.
iii. A different IP address must be assigned to each device.
iv. The first usable IP address is usually given to the default gateway.
v. The last usable IP addresses are usually give to devices that don't change on network.
1. File Servers
2. DHCP Servers
3. Web Servers
4. Printers
7. MAC Address
a. A permanent address burned into your computer's motherboard.
b. It is unique in the world and comprised of 12 hexadecimal digits.
8. Console Commands - Accessed with "CMD" command
i. IPCONFIG - Shows the basic IP configuration of your computer including IP Address, subnet mask
and default gateway.
ii. IPCONFIG/ALL - Show basic and advanced IP configuration information.
iii. PING <IP Address> - Basic network connectivity command.
iv. TRACERT <IP Address> - Shows all the router hops from you to destination network
v. ARP -A
- This command shows all the IP Address that you know how to get to on your LAN.
vi. GETMAC - Find your MAC address
IP Addressing Problems
IP Address
Class (A, B or C)
192.168.1.0
150.77.255.255
105.115.254.210
201.100.11.112
144.12.0.255
88.1.0.0
Subnet Mask
Octet Type
# of IPs
Type(N, H, B)