closing a port,to make sure of single application at one port

[vni]

Hi all,
Can anyone help me,in closing a port.
wat i want is,i want to make sure that no application is running at a particular port.
How to do this,in C language.

[ahoodin]

One possiblility is to check tcp headers of incoming packets. Firewalls work in this manner:

http://www.codeproject.com/internet/FwHookDrv.asp

HTH,

[vni]

Hi,
Thanks for the reply.
I want to close particular port using C language on linux OS.
And can we use firewalls in Linux environment also?
And cant we do that manually using socket programming?

Thanks in advance.

[ahoodin]

http://www.linuxjournal.com/article/1212

[vni]

ha,i find that.Thanks for the help.