bash shell script and associated data file to generate a randomized mac-address from selected survey parameters or from the list of known vendor IDs
####USAGE:
macchanger_choice.sh interface [ option | search_string ]
interface eg. wlan0, eth0
search_string eg. tablet, laptop, lenovo, mac\n\
option ouilist - choose random vendor from IEEE list
-e - retain current vendor string and
randomize user suffix three octets
This script will invoke 'ip link set dev interface [down|up|address]', commands typically restricted to system administration roles. ###Requirements: package iproute2 - Your distribution probably already has this installed.
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macchanger_choice.sh - the executable file
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mac_address_survey.output - the data file
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OUI.list - a version of the IEEE list possibly newer than that used by macchanger.
This script has been tested in debian.
Let a user easily select from among known mac vendor strings based upon hardware product device type, manufacturer, product name, or even model number.
Alternatively:
-
randomly select an entry from the OUI list bundled with this script or with package 'maccchanger'.
-
randomize the non-vendor bytes of your mac address.
1] Avoid assigning 'impossible' or 'implausible' addresses
1.1] Because the vendor code has not yet been assigned
1.2] Because the vendor code has been assigned to a
manufacturer of a device/product incompatible with
your use case.
2] Convenient selection of surveyed vendor codes
2.1] Within the script, one can scroll through the
surveyed list and make a selection.
2.2] Have the script randomly select a vendor code from
among survey entries that match a grep search string
eg. "lAPtoP", "samSUNg", "vaio"
2.3] The surveyed list is small, but represents products
commonly available for retail sale at the time of
the survey (2014-01).
2.4] Users can manually customize and add to their copy
of the survey.
If one of your goals in using a random mac address is to emulate some random existing device, then using a truly random assignment will not meet your requirement because many(most?) of the vendor strings have not been assigned, and many of the possible numbers may never be assigned because two of the twenty-four bits are reserved (see below). This script will only generate 48-bit mac addresses using valid and assigned 24-bit vendor IDs. For this, run
macchanger_choice.sh <interface> ouilist
If one of your goals in using a random mac address is to emulate some category of device, then using a random assignment, even from the set of known assigned 24-bit vendors IDs, will not meet your requirement, because a particular vendor may only manufacture hardware incompatible with your use case. For this, run
macchanger_choice.sh <interface> <search string>
This will generate and assign a random mac address from entries in the 'mac_address_survey' file that match your criteria. The sample survey file has 48 entries, all for interface wlan. Most entries are for laptops; some are for tablets. The search string need not be case-sensitive.
If you would like to browse the survey data, and interactively choose from among the selected vendor strings, run
macchanger_choice.sh <interface>
If you want to randomize your mac address but retain the current vendor string identiying the hardware, ie. you only want to randomize the final three octets, run
macchanger_choice.sh <interface> -e
If you want to change your mac address to a specific value, run
ip link set dev <interface> down
ip link set dev <interface> address <xx:xx:xx:xx:xx:xx>
ip link set dev <interface> up
Collecting the data for the sample survey file was the major effort of this project. The data file is formatted as columnated, space delimited plain text, with the following fields:
Interface (eg wlan, eth)
Product Type (eg laptop, tablet)
Product Manufacturer (eg Dell, Sony)
Product Name (eg Inspiron, Vaio)
Product Model # (eg 1545, SVF_13N13_CXB)
24-bit MAC address vendor OUI string
Users are encouraged to add their own survey entries to meet their own requirements.
The survey information was originally recorded in a .ods format spreadsheet (along with other data), saved as csv, and reformatted using:
sort ./mac_address_survey.csv | \
awk -v FS="," 'BEGIN{getline} \
{ gsub(" ","_"); gsub(",,",",_,"); \
$7="";$8="";$9=""; \
printf "%d %s\n",NR,$0; }' | \
column -t \
> mac_address_survey.output
The least two significant bits of the first octet (called octet 0) are reserved and in practice should always be set to zero. Bit 0 is referred to as the M bit, and bit 1 is referred to as the X bit. Per reference [1], "all OUI assignments made by the IEEE RA have M and X bits equal to zero" and "M=1 is not currently assigned". See there for information of the two instances in which the X bit would be one: a CID; or "A very small number of assignments made prior to adoption of IEEE 802 standards"
IEEE[1] demands that this MAC address value never be used
IEEE[1] recommends this value be used for a distinct null identifier, most often indicating the absence of a valid EUI-48
Both macchanger and this script use the IEEE data file, available at:
The IEEE says it updates this list daily as new vendor vendor IDs are assigned.
The list can be converted into the format used by macchanger and by this script, as follows:
awk '$0 ~ "(hex)"{$2="";gsub("-"," ");print}' \
oui.txt > OUI.list
[1] IEEE FAQs: The Registration Authority http://standards.ieee.org/faqs/regauth.html
[2] IEEE Guidelines for Use: Organizationally Unique Identifier (OUI) and Company ID (CID) http://standards.ieee.org/develop/regauth/tut/eui.pdf
Boruch Baum [email protected]
Copyright (C) 2014, Boruch Baum
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA