wht mac adress have localop ( i dfne there 127, 192, 224, assigned ip, upnp) ?


as in many threads i and forum distalk about same thing.

what is the mac adress of loclloop, means pc own roottablle, its a virtual adaptor, else you couldnt assign 2 ips to 1 place.

at least how i get that adress due i assume any pc have a different.


MAC addresses are hardware addresses used by Ethernet to send from one NIC to another. If there is no hardware, as with the loopback device, there is no MAC address corresponding to it. You’re able to assign multiple IP addresses to the loopback device because the device driver provides that ability in order to handle IP packets. Contrast to a video display driver, that doesn’t handle IP packets.

Ethernet itself is another set of protocols. It can handle the Internet Protocol (IP) stuff that CFP is concerned with. Ethernet also handles IPX, Appletalk, the classic Netbeui, and a bunch of others.


take eg. a virtual adaptor like dialup ppp, this have a mac address too.

i understand its impossible to assign different ips (eg. a routing table, software) not have a mac address.

hope i dont get ban here, but how else would you spoof ips if not via mac adress?

anyone have might linux can check this out?



On the FreeBSD 6.2p7 box sitting next to me, virutal adapters like loopback and ppp don’t have MAC addresses. They do have an IP address, and can in fact have several. A normal boot sequence thru /etc/rc does things like this:

ifconfig lo0 inet
ifconfig lo0 inet alias

so the loopback device will respond to both and to

You can do something similar with device ppp0, though the syntax is a little different, as a point-to-point device connection gets very constrained.

To learn more about the actual bits that are on the wire, I’m going to suggest that you download a packet sniffer. Microsoft Network Monitor, Wireshark, or my preference of windump, which is the Windows port of the *ix/BSD standard tool called tcpdump. Windump is available WinDump - Download, and needs the underlying winpcap library.

Both windump and winpcap are about 700kbyte is size. Windump is command line driven, and needs admin privileges to run.

When you can actually see the bits on the wire, things make much more sense.

And, to keep things on topic here, you can really target your CFP rules and know for certain that the rules are correct.

hi grue,

can you create a dialup icon in windows, you dont need select anything and can simply erase it.

then make ipconfig / all, you will see this virtual adaptor have a MAC.

sorry for my unpreciseness, i mean bind ips of different nets.

does work bind 127.x.x.x and 192.x.x.x etc



In between dayjob moments here, I got a chance to check a few things.

On a WinXP Pro SP2 laptop, with Ethernet, wireless, inbound VPN (not an outbound client), and outbound PPP modem defined, only the Ethernet and wireless show has having MAC addresses. I found it interesting that ipconfig /all did not list the VPN, PPP, or loopback devices.

On FreeBSD 6.2p6, PPP devices and loopback do not have MAC addresses. PPP has a capability called ‘proxyarp’ that is used as a part of routing, but it’s not part of the device interface itself. The terminology might be the confusion.

That checking did produce a question for me though, and that is a different topic for the forum.


hi soya, this is obvious a comodo problem, because if my statement is true,

comodo would be first cover this hole ever since pc.

so move back item, that ppl can discuss, and comodo can evtl. loopback not controlled by ip then by mac- adress,

means ip spoof is not able any more.


PS: else there might a authorities backdoor?

On Win platform, PPP devices are assigned a dud MAC when they are activated. Defining them just builds the “framework” for the connection to be bolted onto. Do an ipconfig /all before, during and after dialling and you’ll see the IP details change as the adapter initialises.

Ewen :slight_smile: