What is the use of each ports? is this the default port numbers?

why we are using ports ? whats the use of each?

Hi Jaison,

Here's a posted list of all of the well-known ports.  It's a lot more than you want to read, but the first couple of dozen will be names that you may recognize.  FTP, TELNET, SMTP (mail), SNTMP (network management), SSH, and others.

  http://www.iana.org/assignments/port-numbers

It might help to think of an IP addess as a phone number.  When you call corporate headquarters, someone nice office admin answers and asks you who you want to talk with or asks you for an extension.  The phone number gets you a switchboard, the extension gets you to a particular phone.

The IP address/Port number works the same way.  The IP address gets you to a server, the port number gets you to a particular service or application on the server.


Good Luck,
Kent

ok..above all are tcp ports right? mostly we use only tcp ports ? whats the speciality of this ?

ftp - 21     -------- > this is for file transefer ..so file transfer through this port ..right?
pop - 100----------> i dont know
pop3 - 110 --------> for mails does mails comes through this? :-) whats the difference from above?
telnet - 23 ---------> for telnet sessions
ssh - 22 -----------> for ssh..secure transactions...but where we used this?
smtp - 25-----------> again for mail?
http - 80------------>  is this for website?
https - 443---------> website using secure protocol ... but what is the difference between ssh?

Please clarify my doubts!!

Thanks in advance!

thanks a lot of info..

is this comes in the category tcp ? why so ?

is there any other categorizes ? what is the specialty of tcp ?

Some ports will accept and communicate TCP sessions, some UDP sessions, others both.

There aren't a lot of differences between TDP and UDP, but the differences are significant.

The biggest difference is that packets sent over a TCP session are collected in the IP stack and passed to the application in the order that they were sent.  (It may be that a connection has about 15 routers between the client and server.  The packets don't all have to follow the same route, so it's possible that the can arrive out of order.  The TCP protocol requires that the packets be delivered in the correct order.)  UDP packets can arrive in any order.

TCP,  UDP, and ICMP are the 3 types of sessions that you're likely to see.  ICMP is how the network handles things like ping and traceroute.


Kent

You mean this port will work in UDP also?

ftp - 21
pop - 100
pop3 - 110
telnet - 23
ssh - 22
smtp - 25
http - 80
https - 443


if no , which will work in UDP?

Any port can use TCP or UDP.  There's no limitation there.

The key element is to know which protocol (TCP, UDP) the server on a given port will connect.  Most servers will connect ONLY to TCP.  It makes no sense to have packets arrive out of order for FTP, SSH, TELNET, MAIL, etc. since the data would be all jumbled up.

For the list that you last posted, I believe that they will respond only to TCP connection requests.

Kent