Download Ports and IPv6

Ports and IPv6
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Ports
Transmission Control Protocol (TCP) or the User Datagram
Protocol (UDP), used for communication
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Generally speaking, a computer has a single physical
connection to the network. All data destined for a particular
computer arrives through that connection. However, the
data may be intended for different applications running on
the computer. So how does the computer know to which
application to forward the data?
 Through the use of ports. Data transmitted over the Internet
is accompanied by addressing information that identifies
the computer and the port for which it is destined. The
computer is identified by its 32-bit IP address, which IP
uses to deliver data to the right computer on the network.
Ports are identified by a 16-bit number, which TCP and
UDP use to deliver the data to the right application.
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[From sun.com]
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Ports
Port numbers range from 0 to 65,535 because ports are
represented by 16-bit numbers. The port numbers
ranging from 0 - 1023 are restricted; they are reserved
for use by well-known services such as HTTP and FTP
and other system services. These ports are called wellknown ports.
 There are 65,535 port numbers available for application
processes that use Transmission Control Protocol
(TCP). The same number of ports are available for
application processes that use User Datagram Protocol
(UDP).
[from sun.com]
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Ports
Default TCP Port
Number
Internet Service
20
File Transfer Protocol (FTP) Data Channel
21
File Transfer Protocol (FTP) Control Channel
23
Telnet (enabled on some intranet or Internet servers)
25
Simple Mail Transfer Protocol (SMTP)
80
Hypertext Transfer Protocol (HTTP) used for World Wide Web
119
Network News Transfer Protocol (NNTP)
443
Hypertext Transfer Protocol over TLS/SSL (HTTPS) for secure World Wide
Web
563
Network News Transfer Protocol over TLS/SSL (NNTPS)
UPD Port Number
Service
53
Domain Name System (DNS) name queries (supports some Internet services)
161
Simple Network Management Protocol (SNMP)
From Microsoft.com
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IPv6
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Present IPv4 is used
This is 32 bits, and has about 4,300,000,000
address spaces (2^32 – 1)
IPv6 is started to be implemented.
IPv6 is 128 bits giving 3.4 x 10^38
addresses
Allows for an (almost) inexhaustible supply
of addresses.
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