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

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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?

Re: Does the laptop NIC MAC address ever get past your home broadband router?
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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?

--  
http://www.greenend.org.uk/rjk/

Re: Does the laptop NIC MAC address ever get past your home broadband router?
On Tue, 26 May 2015 13:10:57 +0100, Richard Kettlewell wrote:

> In IPv4, the answer is ?no?.  IP packets don?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?

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

That is a given. :)


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

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

How can I turn off IPv6?

> What sort of threat are you worried about?

Privacy.  
I just don't want my unique MAC address tagging all my communications.


Re: Does the laptop NIC MAC address ever get past your home broadband router?
Will Dockery writes:
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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  
jhasler@newsguy.com
Dancing Horse Hill
Elmwood, WI USA

Re: Does the laptop NIC MAC address ever get past your home broadband router?
Hello,


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It does if it provides and owns "your" broadband router.

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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

privacy, hah!, was: Does the laptop NIC MAC address ever get past your home broadband router?
Quoted text here. Click to load it

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

--  
_____________________________________________________
Knowledge may be power, but communications is the key
             dannyb@panix.com  
[to foil spammers, my address has been double rot-13 encoded]

Re: privacy, hah!, was: Does the laptop NIC MAC address ever get past your home broadband router?

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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

--  
Change nomail.afraid.org to ody.ca to reply by email.
(nomail.afraid.org has been set up specifically for
use in usenet. Feel free to use it yourself.)

Re: privacy, hah!, was: Does the laptop NIC MAC address ever get past your home broadband router?
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$ tree -ifa /usr/share/fonts|wc -l
ksh93: tree: not found
0
$ find /usr/share/fonts -type f | wc -l
883
$

But:

Browser              bits of               one in x browsers
Characteristic   identifying information    have this value      value
User Agent           12.12            4443.21         Mozilla/5.0
                                                                X11; Linux
                                x86_64;
                                rv:38.0)
                                Gecko/20100101
                                Firefox/38.0
...
System Fonts        2.3            4.91        No Flash or
                                                                Java fonts
                                detected

My point: you can have a lot of fonts but not let the browser share that
list. (And /usr/share/fonts isn't all my fonts, since I install some in
~/.fonts/ )

Elijah
------
has fonts in only two of four directories named in /etc/fonts/fonts.conf

Re: privacy, hah!, was: Does the laptop NIC MAC address ever get past your home broadband router?
On Thu, 4 Jun 2015 22:11:53 +0000 (UTC), danny burstein

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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.

Re: privacy, hah!, was: Does the laptop NIC MAC address ever get past your home broadband router?

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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.
   ----
- lots and lots of info, with numerous differences
  between the two browsers.


--  
_____________________________________________________
Knowledge may be power, but communications is the key
             dannyb@panix.com  
[to foil spammers, my address has been double rot-13 encoded]

Re: privacy, hah!, was: Does the laptop NIC MAC address ever get past your home broadband router?
On Fri, 5 Jun 2015 02:32:48 +0000 (UTC), danny burstein

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    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
    
--  
Don't be evil - Google 2004
We have a new policy  - Google 2012

Re: Does the laptop NIC MAC address ever get past your home broadband router?
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The ISP presumably knows who they have a contract with, though.

--  
http://www.greenend.org.uk/rjk/

Re: Does the laptop NIC MAC address ever get past your home broadband router?
On Tue, 26 May 2015 13:10:57 +0100, Richard Kettlewell wrote:

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

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

#!/bin/bash
if [ $# -eq 0 ]
then
    echo -n "Enter WLAN0 MAC: "  
    read WLAN0
else
    WLAN0=$1
fi  
echo "Comparing MAC IDs"
OLD_WLAN0=`ifconfig wlan0|grep HWaddr|awk '{print $5}'`
if [ "$OLD_WLAN0" != "$WLAN0" ]
    then
        sudo ifconfig wlan0 down
        sudo ifconfig wlan0 hw ether $WLAN0
        sudo ifconfig wlan0 up
        NEW_WLAN0=`ifconfig wlan0|grep HWaddr|awk '{print $5}'`
        echo "   Good: \$NEW_WLAN0=$NEW_WLAN0 is now the same as \$WLAN0=$WLAN0"
    else
        echo "   Good: \$OLD_WLAN0=$OLD_WLAN0 was already set to \$WLAN0=$WLAN0"
fi # if MAC needs to be changed, change it & move on; otherwise move on.

sudo service network-manager restart
exit 0


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