cooloutac: > 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. > I haven't looked into the security risk for dhcp connection. I intend to look into it and adjust accordingly. Thanks for the suggestion.
-- qubenix GPG: B536812904D455B491DCDCDD04BE1E61A3C2E500 -- 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/bb62f68f-75e4-677d-462d-44b0872d72ec%40riseup.net. For more options, visit https://groups.google.com/d/optout.
