WiFi MAC Address Changes on Every Reboot

[Iceman0803]

Title says it all. From what I understand the issue is present in devices whose MAC address begins with 00:90:4C, as mine does, and after every reboot the last 6 values will change. Just curious as to how many others are out there with the same issue. It would be interesting to know if it only affects the aforementioned 00:90:4C devices or if others are included as well. Also, to anyone that is aware of the issue, is it a SW or HW issue? I'm curious because if it is indeed HW related (as I think it may be) I need to exchange my Nexus soon. If it is indeed SW related though I'm fine waiting for a fix. Not sure about my network admins though lol.

There's a ticket open with Google regarding the issue as well: http://code.google.com/p/android/issues/detail?id=23330

EDIT: Poll added

 

[CynicX]

Read your link. Is this an issue a replacement can fix? Someone mentioned it's only with devices starting with a certain Mac address.


iPhone 4s using Tapatalk

 

[Iceman0803]

Read your link. Is this an issue a replacement can fix? Someone mentioned it's only with devices starting with a certain Mac address.


iPhone 4s using Tapatalk

That's exactly what I'm trying to figure out. Some have been told it's a HW issue and have gotten replacements, while others have been told that it's a SW issue. As far as it only affecting certain MAC addresses, that's the purpose of the poll. To get an idea of weather or not that is true.

 

[DukeSilversJazz]

When I got home on Dec 15, I wrote down my MAC to keep track of it on my list of MAC's, and here's what I wrote down: 2C-44-01-C7-6F-77, not at all in the range right of the MAC address reporting the issue.

No issues until last Thursday (Jan 19th). Wouldn't connect, only after verifying the password was correct, I looked at the router for the MAC listed on the Allowed List for MAC Address Filtering. My phone now had an address starting with 00-90-4c. How/Why? MAC addresses are NOT supposed to change, EVER. Even reverted to factory 4.0.2 without associating it with any wifi, same result, last 3 octets change every reboot. I had to disable MAC Address Filtering on my router at home, but at work I cannot.

I've spoken with Samsung/VZW about this, GalaxySSupport via Twitter, and posted on the Google Code page. There was kernel code identified that will randomize a MAC address, but I don't know why it isn't affecting everyone, or if it a certain MAC address block range (serial #, or ?)....?

Very annoying. I'm not sure if it is hardware or software, but personally I am leaning towards software given the kernel code that I've seen posted.

 

[vicw926a4]

I responded NO to the poll, but then realized your poll question is specifically about the Galaxy Nexus.

I've been using MAC address security filtering in my routers for years, and have all of my known wired and
wireless device MAC codes recorded, and have never experienced any device that changed its own hardware MAC code, but I don't own a Galaxy Nexus, yet. My apologies for giving a bogus NO response.

 

[daitsuwamono]

MAC address filtering doesn't really qualify as a security measure. MACs are not necessarily unique, default address ranges are used on a per-brand basis, and they are reassignable and readily spoofable in many cases. The solution here seems to be, in my eyes, stop kidding yourselves and using MAC filtering on your routers.

Turn WPA2 Personal with AES encryption, generate a very long, random password, and you'll have no problems. Or, if you're paranoid, set up a RADIUS server for your LAN.

 

[vicw926a4]

Yes, I. Use WPA2 in addition to MAC filters.

Sent from my DROIDX using Tapatalk

 

[cbwx34]

I had this problem with the first Nexus I got...

http://forums.androidcentral.com/verizon-galaxy-nexus/141613-mac-address-changed.html

I called Verizon support... who eventually transferred me to Samsung, where I spoke with a guy who said he was an engineer,,, as soon as I described the problem,,, he told me it was a hardware issue and to get a new phone.

 

[lakaw]

Got mine replaced at the Verizon store under the 30 day window.

 

[CrazyRussian007]

Here is what I've read on other forums from a an avid kernel developer about the MAC/Samsung/Google: there is a code in kernel to actually use a random generated MAC addresses. He even posted a code snippet from the Google image. It appears that instead of buying a range for MAC addresses and assigning each phone with one, Samsung/Google used a MAC generator for the use on the phone. I dont know if it was financial decision or technical.

 

[Iceman0803]

Here is what I've read on other forums from a an avid kernel developer about the MAC/Samsung/Google: there is a code in kernel to actually use a random generated MAC addresses. He even posted a code snippet from the Google image. It appears that instead of buying a range for MAC addresses and assigning each phone with one, Samsung/Google used a MAC generator for the use on the phone. I dont know if it was financial decision or technical.

The odd thing about it is that it seems to affect just a certain range of addresses and not all addresses used for the GNex.

 

[migamix]

ok, it is a software issue... i know this because my Droid X had the exact same issue after flashing a cyanogen rom. from that point on it was randomizing the last 6 places, but... i solved the issue buy running some commands in terminal that forced the address to remain, this is something that some rom devs need to watch out for, your trashing our static MAC addresses guys.... now, this problem has just started for me because this seemed to have started after running AOKP, and someone has botched something someplace... im looking up that pages now, but im almost willing to try it on my Gnex, im thinking its an Android level fix, not a hardware specific thing...

some links to look at, for the devs... the command beginning with / w p 1 l 2 f 2 is what i have as the area of scripting that fixed it... im working on looking for the links

these are in NO WAY stated for the Gnex, and would i recommend using them as a fix, but this is a good place to start on getting this fixed... and proof it is software level... if you try to claim that you didnt root your device, but you did, then your wasting your time by not giving all required information... if you really have not rooted, and have this issue, then by all mean press the matter to google, it means something in an update failed... read up ... and good luck

if i run across and test the actual fix, ill be back, i noticed this issue just a litle late in the evening, as im still on less that 24 hours with AOKP rom... ill try to flash back to a nandroid of another rom like gummy, but this usually doesn't fix the problem... will let you know

oh yeah... PS ... when i got this phone, and had enable a fixed ip on my router the first 6 numbers were 2C:44:01

if i remember right, the first one was the page i used to fix my DX
http://rootzwiki.com/topic/5650-wip-guide-nvs-map-creation-aka-how-i-fixed-my-wifimac-issues/
Template:OMAPpedia/WLAN Calibration - OMAPpedia
cm7 mac address fix - xda-developers

 

[almahix]

Has anyone developing kernels fixed or created a workaround for this? Google doesn't care, so it is up to the dev community to fix it, but as far as I know, no developer has encountered this on his or her phone. Otherwise it would be fixed. Please developers, can't somebody fix their kernel to read the /factor/wifi/.mac.id file to get the real mac id of the device, or add some kind of mac id 'clone' feature so we can work around this?

 

[pool_shark]

MAC address filtering doesn't really qualify as a security measure. MACs are not necessarily unique, default address ranges are used on a per-brand basis, and they are reassignable and readily spoofable in many cases. The solution here seems to be, in my eyes, stop kidding yourselves and using MAC filtering on your routers.

Turn WPA2 Personal with AES encryption, generate a very long, random password, and you'll have no problems. Or, if you're paranoid, set up a RADIUS server for your LAN.

I disagree that it doesn't help.
Even if you can spoof a MAC address, you'll have to find one that matches one that is allowed on the network.

 

[Petronel Laviniu Malutan]

yes is a security measure. You will not get at all a connection to the router wo a known mac, then you will have to input a password... so changing mac addr at every wifi restart is a bug / annoying issue ! I would like to know how to fix it ... there is any shell command to run after connecting with ssh to the phone ?

 

[BDRymell]

I've just realised this is happening on my 2 week old Cubot S208 device. Initially I couldn't understand why I could get connection to home wi-fi whne it had been working previously. I have MAC address filtering on my home router. I entered the new MAC address into my router and device connected straight away. Today the device refused to connect again and noticed MAC address has changed again, so had to update my router again. The MAC address in my device begins with 68 9C 5E, and as the others have reported, it's the last 6 digits that keep changing. Very annoying as I need to use the device at home more than I do outside.

 

[Tr Sands]

I just purchased a POSH S580A and it has the same issue. Everytime I reboot the MAC changes. I have MAC filtering on my primary WIFI and this is quite annoying. I see that this issue goes back several years which is even more annoying . Anyone have a solution?

 

[bugmenot2k15]

Digging a old topic I found while looking for a fix for the same issue on different hardware/os.

I have a couple answers to add that could help better understand this issue.

How/Why? MAC addresses are NOT supposed to change, EVER.
(...)
Very annoying. I'm not sure if it is hardware or software, but personally I am leaning towards software given the kernel code that I've seen posted.

The MAC address is the equipment is not changing, the one the OS gives to the equipment is.

It is supposed to do so to deal with faulty hardware and driver which returns an invalid MAC address, using the invalid MAC would further break many things so as a workaround when and invalid MAC address is detected, the OS uses a random one instead.

This is usually triggered by a software issue with drivers returning the wrong MAC address, a common case is the MAC being reversed.

RFC 2469 addressing this issue has been aroudn since late 1998 but the issue still lives today, see tools.ietf.org/html/rfc2469

The odd thing about it is that it seems to affect just a certain range of addresses and not all addresses used for the GNex.

It has to do with reserved type addresses and misreading the canonical form of a MAC address or LSB format.

As explained in the RFC linked above:
LSB format is best defined as how the bit order of an adapter address on the LAN media maps to the bit order of an adapter address in memory: The first bit of each byte that appears on the LAN maps to the least significant (i.e., right-most) bit of each byte in memory. This puts the group address indicator (i.e., the bit that defines whether an address is unicast or multicast) in the least significant bit of the first byte.

When the MAC address is read with inverted byte order, it means every last digit higher than 7h will trigger the multicast type case during attendibility check and cause the MAC to be deemed invalid.

It could be something different triggering the issue, but chances are some range are unaffected because when read wrong they're still part of valid range and not falling into a reserved one.

 

[bugmenot2k15]

I disagree that it doesn't help.
Even if you can spoof a MAC address, you'll have to find one that matches one that is allowed on the network.

Disagree all you want, the only case it helps is when no client is connected to the wifi network. MAC filtering only gives a false sense of security on par withnot broadcasting the SSID. By nature WiFi broadcast to everyone in range the MAC adresses connected to it and any passive listener can collect them.

If there a lower hanging fruit around, an impatient roadwarrior will get the other one, but if your network is the only one around or you're facing someone who wants to get into your network, MAC filtering won't deter anyone as wpa2 aes would.

I usually set up my device to monitor the radio and leave it for 24h then come back and it usually has collected at least a couple of MACs and enough IVs to crack the key. The longest I had to wait was a week then it's free wifi, that can be used for nefarious purposes as it can't be traced back to me or my MAC while the owner thinks he's smart and protected because he enabled mac filtering.

 

[eaeapepe]

It takes like 2 seconds to get a list of all the MAC addresses connected to a wifi, without even having to connect to it to find out. The data is in the air

Funny, I came to this thread thinking... how cool, I can anonymize my device by automatically changing my MAC address! Others just complain about this awesome feature