While there still are a few tools that want an IP address on an interface, most (including tcpdump) are fine without one. What may be happening is that the interface is down, but the tool you're using to assign the interface also brings it up. try: (substitute your interface for "eth3") # ifconfig eth3 up or # ip link set eth3 up (depending on whether you're used to using "ifconfig" or "ip") Either of these commands will bring the interface up without assigning it an IP address. Tcpdump works fine for me in this fashion. Regards, Brad ------------------- Good luck or good manuals, which do you want? On Mon, 22 Sep 2008, Chris Fowler wrote: > Kris van Rens wrote: > > > > However, SIOCGIFCONF does not return interface information of > > interfaces that have no IP-address, so this method was rejected due to > > the need for this capability. > > > This might be related to an issue I am having. I have a box with a 4 > port RouterBoard. I'm using all 4 ports in a bridge to sniff parts of the > network. Since the bridge is not part of the network, I do not assign > an IP address to it. Tcpdump complains and some 3rd party sniffing > programs > refuse to work. The emit an error and terminate. My fix has been to assign > a random IP address not on the host network. > > Why am I required to assign an address to an interface used only > for promiscuous mode? > > Chris > > -- > To unsubscribe from this list: send the line "unsubscribe linux-net" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
