IP Adressing in IPv4 By Kenneth Lundby

IPv4 Addresses Basics about IP addressing Ipv4 classes and structures NAT Domain names and IP

Basics about IP addressing Operates in the Network Layer of the OSI model IPv4 was the first iteration of the protocol to be widely deployed 32 bit addresses Over 4 billion different addresses

IPv4 classes and stucture 32 bit addresses Divided into 4 octets 10.0.0.4 00001010.00000000.00000000.00000100 Divided into classes Defines what is the Network-ID and what is the Host-ID Originally the first octet was the Network ID and the last 3 was the Host ID

IPv4 classes and structure Now we have class A, B & C Networks Class A: 112.14.38.56 where 112/the first octet is the Network ID, the rest is the Host ID Class B: 136.14.38.56 The 2 first octets are the Network ID Class C: 200.14.38.56 The first 3 octets make up the Network ID In a class A network you can only have 256 networks, while in a Class C network you can have 2 million networks, you can only have 254 hosts on each

NAT Network Address Translation Translation from public to private IP addresses Resolve issues with to few IP addresses Private IP addresses: 10.0.0.0 - 10.255.255.255 Class A 172.16.0.0 - 172.31.255.255 Class B 192.168.0.0 - 192.168.255.255 Class C 169.254.0.0 – 169.254.255.255 Class C

NAT You usually only have 1 single public IP address This would then typically be your Gateway The gateway handles all traffic in and out It translates and sends the packets to the right destination

Domain names and IP IP addresses are hard for humans to remember Domain Name Server Nslookup 144.80.128.80 = www.iup.edu Is like a phone book Name Servers are distributed over the Internet

The End Questions? Resources: http://www.iu.hio.no/%7Ehaugerud/osa/Forelesning/os/node5.html http://en.wikipedia.org/wiki/IPv4