Hi experts,

I tried telnet command :
telnet 192.168.1.22 80

80 is port number.
then ^] and i pressed ENTER

but NO OUTPUT, WHY?

My problem is I want to know the applications running on any particular port number.Which command will be uuseful? either telnet or ?

Port 80 is the HTTP server. If you'd read up on the HTTP protocol, it works by the client first sending commands, and only after this is done the server responds (repeat as necessary).
Try this: telnet 192.168.1.22 80. As soon as it's connected, enter "HEAD / HTTP/1.0" followed by hitting return twice. In the output, look for a line like this
This tells you that the server uses Apache 2.2.3 running atop SuSE Linux.

Your other option is to install nmap and use the service version scan.

Thanks pludi,
But my altimate aim is to know :

What all are the application runninig on any particular port number either
port 80 or 22 doesn't matter. I have just tried telnet for the same but
i need the right command for this:

What all are the application runninig on any particular port number either
port 80 or 22 doesn't matter ? ?

The lsof(8) command can be run as follows:
And as you can see list what process has opened what port. See also http://www.opensource.apple.com/darw...f/00QUICKSTART.

thanks TonyFullerMalv,
But can u please tell me which of the column will give me the port no here..
# lsof -i
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
avahi-dae 5033 avahi 14u IPv4 15387 UDP *:mdns
avahi-dae 5033 avahi 15u IPv4 15388 UDP *:33378
cupsd 5081 root 2u IPv4 15468 TCP localhost:ipp (LISTEN)
hddtemp 5136 root 0u IPv4 15530 TCP localhost:7634 (LISTEN)
dhclient 6014 root 5w IPv4 20112 UDP *:bootpc
thunderbi 9118 tony 32u IPv4 88273 TCP laptop.local:47532->ey-in-f111.google.com:imaps (ESTABLISHED)
thunderbi 9118 tony 33u IPv4 88277 TCP laptop.local:54941->moz.com01.nslb.sj.mozilla.com:www (ESTABLISHED)
thunderbi 9118 tony 34u IPv4 88282 TCP laptop.local:58086->2.stage.mozillamessaging.com:www (ESTABLISHED)
thunderbi 9118 tony 35u IPv4 88294 TCP laptop.local:38661->1.stage.mozillamessaging.com:www (ESTABLISHED)
thunderbi 9118 tony 36u IPv4 88295 TCP laptop.local:38662->1.stage.mozillamessaging.com:www (ESTABLISHED)
#

The port number is after the colon, some have been translated into their names using their respective numbers from /etc/services presumably, .e.g.:

:7634
or
:www (port 80)
or
:ipp (port 631)