Re: How To Temporarily Suspend Network Traffic
On Tue, 1 Feb 2011 13:15:15 -0500, Gregory Seidman writes:
> On Tue, Feb 01, 2011 at 07:40:06PM +0200, Volkan YAZICI wrote:
>> [...]
>> # while /bin/true; do \
>> > iptables -A OUTPUT -i wlan0 -j DROP && \
>> > usleep 100000 && \
>> > iptables -D OUTPUT -i wlan0 -j DROP
>>
>> command (usleep is a small C program I wrote, see the attachment),
>> transfer hangs after some point and stops for ~30-40secs and finishes
>> when I stop the while loop. Do I miss anything? Any suggestions?
>
> Here you are interrupting for 100,000 usecs (which is 100msecs, I believe),
> but you don't sleep at all between interruptions in the while loop. That
> means that it only has the time between the execution of the iptables
> command at the end of the loop and the execution of the iptables command at
> the beginning of the loop to actually transmit any packets. It is
> unsurprising that it hangs. Make sure you sleep for a while after removing
> the iptables rule.
Indeed, sleeping more than I want is what I try to avoid. In other
words, I'm inclined to believe that running iptables externally doesn't
provide an interruption mechanism in milli/microsecond granularity. Any
other suggestions?
Regards.
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