IP address and Port
August 7, 2009
Every machine on the Internet has a unique identifying number,called an IP address.The IP address 0.0.0.0 is reserved for the default network and the address 255.255.255.255 is used for broadcasts.
IP v4 (Internet Protocol Version 4) Address Networks:
Currently three classes of networks are commonly used.These classes may be segregated by the number of octets used to identify a single network.Addressing scheme used in IPv4 is 32-bit.
Class A Networks (the largest) are identified by the first octet,which ranges from 1 to 126.
Class B Networks are identified by the first two octets,the first of which ranges from 128 to 191.
Class C Networks (the smallest) are identified by the first three octets,the first of which ranges from 192 to 223.
IP v6 (Internet Protocol Version 6) Address Networks:
IPv6 is a new standard protocol intended to replace IPv4 for the Internet.Its large address space is not proposed to provide unique addresses.Addressing scheme used in IPv6 is 128-bit.
IPv6 provides better capabilities to support autoconfiguration (such as DHCP),multicasting,traffic engineering and zero configuration networking.IPv6 requires IPsec support.
Port allows a computer to differentiate services such as E-mail data from web data.Port is a special number present in the header of a data packet.Ports are typically used to map data to a particular process running on a computer.
Ports are classified into 3 types:
Well known Ports ￢ﾀﾓ 0 to 1023
Registered Ports ￢ﾀﾓ 1024 to 49151
Dynamic/Private Ports ￢ﾀﾓ 49152 to 65535
For Example, SMTP server has default port number 25 and POP3 server has 110