How to kill network connection in Solaris/BSD ?

Why do you want to kill them? What problem are they causing? If the applications are using that port, then killing the
port is definitely an abnormal event and will cause the applications to be very annoyed at the least. There is a way to
kill network connections on Solaris, but it uses an undocumented ioctl, and Sun doesn't like to publicize it too much, because it is a "last resort" kind of thing.

OT
blu: it can be used to disconnect annoying users for example ;)

blu, yup.. i want to kill the unwanted and annoying application which is causing load to my bandwidth..
How to use 'ioctl' as the last resort ?

did you try lsof? If it is not installed then you can download and install from sunfreeware.com.

Did you check bigadmin ? They have a great article for that issue :

http://www.sun.com/bigadmin/content/submitted/tcpdrop.jsp

sure I will check tcpdrop and lsof.. just for more info, is it possible to use 'fuser' to get this information.. ??

Yes, you can also use fuser for that purpose. Example :

fuser ssh/tcp

$fuser ssh/tcp
ssh/tcp: fuser: No such file or directory

Though I can see sshd daemon is running in my system.

the fuser on solaris does not support ports.

Thank you! :)