Network Addressing TEJ 3M

MAC Address (Media Access Control Address) Hard wired into your network card by the manufacturer Hard wired into your network card by the manufacturer Every network card in the world has a different MAC Address Every network card in the world has a different MAC Address Example: B B4 Example: B B4 Analogy: A MAC address is like your name; it stays with you wherever you go Analogy: A MAC address is like your name; it stays with you wherever you go

IP Address Your unique address on the Internet Your unique address on the Internet Every device connected to the Internet has a unique IP address Every device connected to the Internet has a unique IP address Example: (the four portions are called octets. Each octet can hold numbers in the range of 0-255) Example: (the four portions are called octets. Each octet can hold numbers in the range of 0-255) You IP address will depend on where you connect to the Internet You IP address will depend on where you connect to the Internet Analogy: An IP address is like your home address. It changes when you move. Analogy: An IP address is like your home address. It changes when you move.

Finding Your IP Address In DOS, you can use the command “ipconfig” In DOS, you can use the command “ipconfig” In reality, this might not be your actual IP on the Internet, due to an advanced concept called “Network Address Translation” In reality, this might not be your actual IP on the Internet, due to an advanced concept called “Network Address Translation” There are also websites that will tell you your IP on the Internet. Example: There are also websites that will tell you your IP on the Internet. Example:

Network vs Host The first part of an IP address (often the first three octets) identifies the network you are attached to The first part of an IP address (often the first three octets) identifies the network you are attached to The last part of an IP address identifies your host (ie, which computer you are on the network) The last part of an IP address identifies your host (ie, which computer you are on the network) Example: , might mean, you are computer 3, on the network Example: , might mean, you are computer 3, on the network Note: It is possible to divide up an IP address into network/host within an octet Note: It is possible to divide up an IP address into network/host within an octet

Subnet Mask Specifies which part of the IP address represents the network, and which part represents the host Specifies which part of the IP address represents the network, and which part represents the host Examples: Examples: – – First three octets are network, last octet is host – – First two octets are network, last octet is host –If your IP address is , and your subnet mask is , then Your network is Your network is Your host is Your host is

Gateways Attaches a network to the rest of the Internet Attaches a network to the rest of the Internet A special type of router – will forward packets destined for a location outside the local network A special type of router – will forward packets destined for a location outside the local network Drops broadcast packets Drops broadcast packets

Example of Packet Destination IP Address is IP Address is Subnet Mask is Subnet Mask is Packet going to will go to the gateway Packet going to will go to the gateway Packet going to will not go to the gateway Packet going to will not go to the gateway

Maximum possible computers on a network IP address limit this IP address limit this 254 possibilities for each octet 254 possibilities for each octet Example: For a subnet mask of (very uncommon) Example: For a subnet mask of (very uncommon) –Three octets available for host address –Therefore, number of possibilities is: 254*254*254 = *254*254 =