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-   -   intel 2.4Ghz wifi has 2 mac addresses? (https://www.linuxquestions.org/questions/arch-29/intel-2-4ghz-wifi-has-2-mac-addresses-4175654380/)

CreakinCrank 05-22-2019 09:01 AM

intel 2.4Ghz wifi has 2 mac addresses?
 
Hi all, first I want to say I am a complete newbie with linux, so please be gentle! Secondly I am not sure if this is the right place to post this, or if this is even related to Linux, I'm just hoping someone here can point me in the right direction if this is the case.

I'm running Arch on an old Acer laptop which came with broadcom networking. After having lots of dropouts & low quality connections over wifi, I thought I'd try an intel mini-pci card which i got (new) for cheap that uses the 2230N chipset. After removing the old b43 driver & firmware, installing iwlwifi & tweaking wpa_supplicant all seemed to be going well, until it came time to set my router security back up. You see I normally use mac filtering on my router to only allow my known mac's to connect, so i had started by disabling this feature until I knew everything was working. After setting up the new card, I went back into the router to re-enable the filter. On the mac filter page my router lists all the devices currently connected by wifi, & it had 2 entries for the laptop, one with the cards mac address which is listed by ip link, and another connection via a mac with a completely different set of values. I though that was very strange, as i've never come across this before, but in the end just added both of them to the whitelist & turned on the filter. All went well until I rebooted the lappy & found the wifi unable to connect. Going back into my routers settings I noticed that the laptop was listed as being connected, but only via the normal mac (as listed by ip link), however there was still no connection on the laptop (no ip or anything - i'm using dhcpcd btw). Disabling the mac filter on the router allowed the card to connect once more, & then checking the routers pages again showed two connections - the "normal" mac, & another random one, completely different to the second mac it had connected with previously! I'm a bit stumped now, as I would really like my mac filtering to be in place, but if the wifi card generates a (second) random mac at each reboot I'm not going to be able to do that. Has anyone ever come across anything like this before?


EDIT:
OK, it appears I may have jumped the gun a bit! The "connected device" with a static mac disappeared after a router reset :doh:, so now I only have one entry for the laptop, yay! Unfortunately the remaining one is the one with the wandering mac, but at least i'm getting search results for that issue!

business_kid 05-26-2019 06:11 AM

It's possible you have 2 wifi cards or a nic and a wifi card showing. If your distro has it, run
Code:

sudo iwconfig
and see whats going on.See what it's calling your wifi.

If your Broadcom card is making a nuisance of itself, try renaming the b43 directory in /lib/firmware
Code:

sudo mv /lib/firmware/b43 /lib/firmware/dodgy_b43
Next time you reboot, that will fail to find Broadcom firmware which is an excellent way of killing it off. Then see what you've got. A random address doesn't matter, as long as the first three number sets are the same, e.g. 192.168.1.xxx. Random addresses are handed out often. If it's worse, then you have an issue. If you have internet, stop worrying. If you don't say what's up.

RickDeckard 06-04-2019 05:51 AM

Someone please correct me if I'm wrong, but that seems to be a function of NetworkManager. I can boot my secondary Arch install (which also serves as the home office VPN server) and find unique MAC addresses assigned on each connection when only one NIC is present.

273 06-04-2019 08:33 AM

I know Macs have this as a security featurea, perhaps it's been added in Newtwork Manager for similar reasons?

273 06-04-2019 10:26 AM

I know Macs have this as a security featurea, perhaps it's been added in Newtwork Manager for similar reasons?

business_kid 06-05-2019 02:19 PM

The OP seems to have gone quiet....


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