On Wednesday, April 12, 2017 at 10:55:08 AM UTC-4, qubenix wrote: > Unman: > > On Tue, Apr 11, 2017 at 06:20:38AM -0700, Dominique St-Pierre Boucher wrote: > >> On Monday, April 10, 2017 at 5:06:30 PM UTC-4, qubenix wrote: > >>> qubenix: > >>>> Andrew David Wong: > >>>>> On 2017-04-09 15:25, Joonas Lehtonen wrote: > >>>>>> Hi, > >>>>> > >>>>>> if you setup MAC randomization via network manager in a debian 9 > >>>>>> template as described here: > >>>>>> https://www.qubes-os.org/doc/anonymizing-your-mac-address/ > >>>>>> you still leak your hostname. > >>>>> > >>>>>> Once your MAC address is randomized you might also want to prevent the > >>>>>> disclosure of your netvm's hostname to the network, since "sys-net" > >>>>>> might be a unique hostname (that links all your random MAC addresses > >>>>>> and > >>>>>> the fact that you likely use qubes). > >>>>> > >>>>>> To prevent the hostname leak via DHCP option (12): > >>>>>> - start the debian 9 template > >>>>>> - open the file /etc/dhcpd/dhclient.conf > >>>>>> - in line number 15 you should see "send host-name = gethostname();" > >>>>>> - comment (add "#" at the beginning) or remove that line and store the > >>>>>> file > >>>>>> - reboot your netvm > >>>>> > >>>>>> I tested the change via inspecting dhcp requests and can confirm that > >>>>>> the hostname is no longer included in dhcp requests. > >>>>> > >>>>> > >>>>> Thanks. Added as a comment: > >>>>> > >>>>> https://github.com/QubesOS/qubes-issues/issues/938#issuecomment-292843628 > >>>>> > >>>>> > >>>> > >>>> Nice. I was just thinking about this after spending some time on my > >>>> routers interface. Thanks for the post! > >>>> > >>> > >>> After testing this, 'sys-net' still shows up on my router interface. > >>> > >>> -- > >>> qubenix > >>> GPG: B536812904D455B491DCDCDD04BE1E61A3C2E500 > >> > >> Did the same test and got the same result. > >> > >> Anyone has a solution? I can always change my hostname for something else, > >> but I would prefer not sending the hostname or finding a way to randomize > >> it!!! > >> > >> Dominique > >> > > > > Strange, because those instructions are standard for removing the > > hostname - I set it as blank, rather than commenting out. If you sniff > > the traffic you will see that the hostname is indeed no longer sent. > > > > Why is it on your router interface? > > My guess is that your router is returning the hostname that it has > > associated with the MAC address. I've seen this happen when changing > > hostname, and the DHCP server returns the *old* hostname as part of > > the DHCP exchange. If you reboot the router and test again, you may find > > that the issue goes away. > > Confirmed. Router was "guessing" that I was 'sys-net', but not from MAC > (which is randomized). I believe it was using process of elimination > based on stored device hostnames (this is not public, devices are pretty > static). Since restarting the router, it give my pc the hostname of a > device which connected automatically to it (the only one it had to > "guess" from). > > > > > You could, of course, set a random hostname from rc.local on each boot of > > sys-net. > > > > unman > > > > > > > -- > qubenix > GPG: B536812904D455B491DCDCDD04BE1E61A3C2E500
But why use dhcp if its a static home connection? I feel that is a security risk for other reasons and always disable it. -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/43eca04b-7f97-4c27-873a-1a85d2920361%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
