need help from networking and linux expert

Hi, Gurus:

Now I am using hping3 to be packet generator, sending customerized pkt
to a switch and then forward to another linux box, on which hping3
recv was enabled. If modify the dest mac from the sender and changed
arp table make sure those pkts could be forwarded out to switch, and
also, the switch flood this unknown unicast pkts out, but somehow
hping3 recv always saying that no pkt received, but if I turn on
etheral capture on the receiving side, then hping3 recv could see all
those pkts, meaning that if I turn on etheral, something got turned on
the linux box, then make sure all those customerized pkts could go
through. anybody knows what has been turned on and anyway for me to
turn on this without ethereral? thanks.

/zhenwu

Hello,

(E-Mail Removed) a écrit :
> Hi, Gurus:

What about non-gurus ? :-\

> Now I am using hping3 to be packet generator, sending customerized pkt
> to a switch and then forward to another linux box, on which hping3
> recv was enabled. If modify the dest mac from the sender and changed
> arp table make sure those pkts could be forwarded out to switch, and
> also, the switch flood this unknown unicast pkts out, but somehow
> hping3 recv always saying that no pkt received, but if I turn on
> etheral capture on the receiving side, then hping3 recv could see all
> those pkts, meaning that if I turn on etheral, something got turned on
> the linux box, then make sure all those customerized pkts could go
> through. anybody knows what has been turned on and anyway for me to
> turn on this without ethereral? thanks.

By default ethereal, like other packet sniffers, puts the specified
network interface into promiscuous mode, allowing it to accept ethernet
frames with any hardware (MAC) destination address. The -p option
reverses this behaviour. Otherwise a network interface which is not in
promiscuous mode ignores incoming frames with a MAC destination address
it does not listen to, i.e. other than its own MAC address, the
broadcast address and multicast addresses it has been set to receive.

You can put a network interface in promiscuous mode manually with
'ifconfig' (man 8 ifconfig) or 'ip link set' (man 8 ip).

No need to be a networking & Linux expert to answer this. :-p

To me, you are expert. Anyway, thanks for your help and make it
work after using ifconfig. thanks again.

/zhenwu

On Nov 19, 1:31 am, Pascal Hambourg <boite-a-s...@plouf.fr.eu.org>
wrote:
> Hello,
>
> a10.p...@gmail.com a écrit :
>
> > Hi, Gurus:
>
> What about non-gurus ? :-\
>
> > Now I am using hping3 to be packet generator, sending customerized pkt
> > to a switch and then forward to another linux box, on which hping3
> > recv was enabled. If modify the dest mac from the sender and changed
> > arp table make sure those pkts could be forwarded out to switch, and
> > also, the switch flood this unknown unicast pkts out, but somehow
> > hping3 recv always saying that no pkt received, but if I turn on
> > etheral capture on the receiving side, then hping3 recv could see all
> > those pkts, meaning that if I turn on etheral, something got turned on
> > the linux box, then make sure all those customerized pkts could go
> > through. anybody knows what has been turned on and anyway for me to
> > turn on this without ethereral? thanks.
>
> By default ethereal, like other packet sniffers, puts the specified
> network interface into promiscuous mode, allowing it to accept ethernet
> frames with any hardware (MAC) destination address. The -p option
> reverses this behaviour. Otherwise a network interface which is not in
> promiscuous mode ignores incoming frames with a MAC destination address
> it does not listen to, i.e. other than its own MAC address, the
> broadcast address and multicast addresses it has been set to receive.
>
> You can put a network interface in promiscuous mode manually with
> 'ifconfig' (man 8 ifconfig) or 'ip link set' (man 8 ip).
>
> No need to be a networking & Linux expert to answer this. :-p