Guy, Thanks a lot for your answer ! This cause me to ask myself: why, in fact, do we need the "any" pseudo-device when sniffing in Linux ? Is there any information that we can get with the "any" pseudo-device when sniffing, that we can't get without it?
Regards, Mark On Thu, Aug 13, 2009 at 3:35 PM, Guy Harris<g...@alum.mit.edu> wrote: > > On Aug 13, 2009, at 2:44 AM, Mark Ryden wrote: > >> I had noticed that when running tshark in Pseudo-device mode (tshark >> -i any), the >> machine does not enter promiscuos mode, whereas in the usual case, >> such as >> thsark -i eth0 (or without "-i" option at all), it does enter >> promiscuos mode. >> (I tested it on Linux). > > There is no notion at the hardware level of a machine being in > promiscuous mode; there is only a notion, for devices on "broadcast" > networks such as Ethernet, of a network adapter being in promiscuous > mode. Neither Linux nor any other OS I know of have any notion of a > machine being in promiscuous mode, either, just of a device being in > that mode. > >> I would appreciate if somebody can explain in few sentences why is >> it so. > > It's because libpcap implements the "any" pseudo-device on Linux by > creating a PF_PACKET socket but not binding it to a particular > device. (On other platforms, it's not implemented at all.) The Linux > socket calls to turn promiscuous mode on don't work on sockets such as > that - the kernel rejects them rather than setting promiscuous mode on > all devices in the system. > > ___________________________________________________________________________ > Sent via: Wireshark-dev mailing list <wireshark-dev@wireshark.org> > Archives: http://www.wireshark.org/lists/wireshark-dev > Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev > mailto:wireshark-dev-requ...@wireshark.org?subject=unsubscribe > ___________________________________________________________________________ Sent via: Wireshark-dev mailing list <wireshark-dev@wireshark.org> Archives: http://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev mailto:wireshark-dev-requ...@wireshark.org?subject=unsubscribe
