[Gllug] Killing network connections

[Alain Williams]

On Fri, Oct 12, 2007 at 06:45:23PM +0100, Robert McKay wrote:
> On 10/12/07, Tom Weissmann <trmsw at yahoo.co.uk> wrote:
> > This is more out of curiosity than necessity...
> >
> > Is it possible to close a network connection that "lsof -i" shows me
> > without sending a message to either of the processes involved? Can I
> > tell the kernel to kill it somehow?
> 
> I'm not really sure what you're trying to achieve exactly.
> 
> You could try something like this:
> 
> gdb -p <pid>
> call close(<fd>)
> detach
> 
> It won't receive any "message", but things that use network
> connections tend to check them now and again to see if they're still
> there.

Trouble with that is that if the process then opens another file/socket
it will probably get <fd>, so the select() loop that it is probably
sitting in will then return and the program will read/write to
the wrong place ... all hell will break loose.

-- 
Alain Williams
Linux Consultant - Mail systems, Web sites, Networking, Programmer, IT Lecturer.
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