Does the laptop NIC MAC address ever get past your home broadbandrouter?

Discussion in 'Wireless Internet' started by Will Dockery, May 26, 2015.

  1. Will Dockery

    Will Dockery Guest

    I'm just curious if the MAC address of the laptop NIC ever gets past my
    home broadband router.

    Assuming my home broadband router is set up with the typical defaults,
    is there any way that the laptop's wlan0 or eth0 MAC address can get
    past the router to an assailant?

    I realize at a wireless hotspot, where I don't control the router, the
    MAC address can be logged - but does a typical home broadband router
    setup prevent an intruder from obtaining the laptop NIC MAC address?
     
    Will Dockery, May 26, 2015
    #1
    1. Advertisements

  2. In IPv4, the answer is ‘no’. IP packets don’t contain MAC addresses.
    Obviously a bit of software on the inside could choose to send your MAC
    address to somewhere else.

    In IPv6, one of the address assignment mechanisms derives the address
    from the MAC. See
    http://en.wikipedia.org/wiki/IPv6_address#Stateless_address_autoconfiguration
    for details.

    What sort of threat are you worried about?
     
    Richard Kettlewell, May 26, 2015
    #2
    1. Advertisements

  3. Will Dockery

    Will Dockery Guest

    On Tue, 26 May 2015 13:10:57 +-0100, Richard Kettlewell wrote:

    +AD4 In IPv4, the answer is +IBg-no+IBk. IP packets don+IBk-t contain MAC addresses.

    That's what I thought. So only a hotel or Starbucks would know what
    your MAC address is, but, at home, the ISP doesn't know your MAC address,
    right?

    +AD4 Obviously a bit of software on the inside could choose to send your MAC
    +AD4 address to somewhere else.

    That is a given. :)


    +AD4 In IPv6, one of the address assignment mechanisms derives the address
    +AD4 from the MAC.

    Yikes+ACE That's bad. Very bad. That means that you're unique, even though
    you may be on various IP addresses+ACE

    How can I turn off IPv6?

    +AD4 What sort of threat are you worried about?

    Privacy.
    I just don't want my unique MAC address tagging all my communications.
     
    Will Dockery, Jun 4, 2015
    #3
  4. Will Dockery

    Will Dockery Guest

    On Tue, 26 May 2015 13:10:57 +-0100, Richard Kettlewell wrote:

    +AD4 In IPv6, one of the address assignment mechanisms derives the address
    +AD4 from the MAC.

    How does this look as a script to change the MAC address at will?

    +ACMAIQ-/bin/bash
    if +AFs +ACQAIw -eq 0 +AF0
    then
    echo -n +ACI-Enter WLAN0 MAC: +ACI
    read WLAN0
    else
    WLAN0+AD0AJA-1
    fi
    echo +ACI-Comparing MAC IDs+ACI
    OLD+AF8-WLAN0+AD0AYA-ifconfig wlan0+AHw-grep HWaddr+AHw-awk '+AHs-print +ACQ-5+AH0'+AGA
    if +AFs +ACIAJA-OLD+AF8-WLAN0+ACI +ACEAPQ +ACIAJA-WLAN0+ACI +AF0
    then
    sudo ifconfig wlan0 down
    sudo ifconfig wlan0 hw ether +ACQ-WLAN0
    sudo ifconfig wlan0 up
    NEW+AF8-WLAN0+AD0AYA-ifconfig wlan0+AHw-grep HWaddr+AHw-awk '+AHs-print +ACQ-5+AH0'+AGA
    echo +ACI Good: +AFwAJA-NEW+AF8-WLAN0+AD0AJA-NEW+AF8-WLAN0 is now the same as +AFwAJA-WLAN0+AD0AJA-WLAN0+ACI
    else
    echo +ACI Good: +AFwAJA-OLD+AF8-WLAN0+AD0AJA-OLD+AF8-WLAN0 was already set to +AFwAJA-WLAN0+AD0AJA-WLAN0+ACI
    fi +ACM if MAC needs to be changed, change it +ACY move on+ADs otherwise move on.

    sudo service network-manager restart
    exit 0
     
    Will Dockery, Jun 4, 2015
    #4
  5. Will Dockery

    John Hasler Guest

    Your IPV6 address can be derived from whatever you want it to be derived
    from and your MAC address can be whatever you want it to be.
     
    John Hasler, Jun 4, 2015
    #5
  6. Hello,

    Will Dockery a écrit :
    It does if it provides and owns "your" broadband router.
    That's neither good or bad. It has advantages and disadvantages.
    If you don't like it, you might be interested in setting
    /proc/sys/net/ipv6/conf/$INTERFACE/use_tempaddr to a value above 1.

    <https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt>
     
    Pascal Hambourg, Jun 4, 2015
    #6
  7. Yikes! That's bad. Very bad. That means that you're unique, even though
    Your browser itself sends out enough info to
    pretty much individually ID you. (I'd bet you
    thought the browser only told the web server
    what brand, so to speak, it was and your
    computer operating system. Hah!)

    Check out:

    https://panopticlick.eff.org/

    yes, that's the GOod Folk at the Electronic Freedom Foundation
     
    danny burstein, Jun 4, 2015
    #7
  8. I get Your browser fingerprint appears to be unique among the 5,442,876 tested so far. Probably because of
    $ tree -ifa /usr/share/fonts|wc -l
    5906

    Regards, Dave Hodgins
     
    David W. Hodgins, Jun 4, 2015
    #8
  9. The ISP presumably knows who they have a contract with, though.
     
    Richard Kettlewell, Jun 5, 2015
    #9
  10. Will Dockery

    J0HNS0N Guest

    Every time I try it using the same Firefox browser several of the
    numbers change. First I was "only one in 2,721,631 browsers have the
    same fingerprint as yours", on the next try I was "unique among the
    5,443,259 tested so far". Either I've got a good sneaky browser or the
    website is a scam. I'm betting on the second.
     
    J0HNS0N, Jun 5, 2015
    #10
  11. Firefox:

    Your browser fingerprint appears to be unique among the 5,443,287
    tested so far.

    Currently, we estimate that your browser has a fingerprint that
    conveys at least 22.38 bits of identifying information.

    Safari on same machine, a minute later:

    Your browser fingerprint appears to be unique among
    the 5,443,288 tested so far.

    Currently, we estimate that your browser has a fingerprint
    that conveys at least 22.38 bits of identifying information.
     
    danny burstein, Jun 5, 2015
    #11
  12. Will Dockery

    Shadow Guest

    I have 11 bits (one in 2600 tested), but I forge my headers
    and do not allow scripting or flash.
    Can't make it less than that.
    The site is legit. Latest versions of Chrome and Firefox can
    ID you no matter what you do, so I use an old version (of Firefox)
    []'s
     
    Shadow, Jun 10, 2015
    #12
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.