Pocster Posted November 25, 2021 Share Posted November 25, 2021 (edited) I always thought these were unique. But it would seem not. 2 raspberry pi's - same mac address. I've rebooted router/switch - still shows the same!!!. I want to give a unique fixed IP to each one ( based on the supposed unique IP address ) but it would seem I can't. Even unplugged one; reboot everything - still the same MAC address!. I thought the whole point of MAC was unique - what do I do!!!???? Edited November 25, 2021 by pocster Link to comment Share on other sites More sharing options...
Pocster Posted November 25, 2021 Author Share Posted November 25, 2021 I should point out when I 'swap' between these 2 it's the same physically connection on the switch. But that shouldn't matter should it?. Google isn't helping me Link to comment Share on other sites More sharing options...
Dan F Posted November 25, 2021 Share Posted November 25, 2021 You need to do some spoofing! Does this not help? https://pimylifeup.com/raspberry-pi-mac-address-spoofing/ Link to comment Share on other sites More sharing options...
SteamyTea Posted November 25, 2021 Share Posted November 25, 2021 (edited) You can set the IP address up on each Pi in software, or use a hostname. Edited November 25, 2021 by SteamyTea Link to comment Share on other sites More sharing options...
Pocster Posted November 25, 2021 Author Share Posted November 25, 2021 1 minute ago, SteamyTea said: You can set the IP address up on each Pi in software, or use a hostname. I know that. But it's a bit tricky when multiple PI's have the same MAC address Link to comment Share on other sites More sharing options...
MJNewton Posted November 25, 2021 Share Posted November 25, 2021 How are you discovering the MAC addresses? On the Pi's themselves (running ifconfig or similar) or is it from the router's view of the world? If the latter then it is likely getting confused and/or showing misleading information. The MAC addresses *will* be unique so keep persisting... Link to comment Share on other sites More sharing options...
SteamyTea Posted November 25, 2021 Share Posted November 25, 2021 what sort of Pi is it, then if I have one similar on my network, can see if it is the same as mine. Link to comment Share on other sites More sharing options...
Pocster Posted November 25, 2021 Author Share Posted November 25, 2021 (edited) 23 minutes ago, MJNewton said: How are you discovering the MAC addresses? On the Pi's themselves (running ifconfig or similar) or is it from the router's view of the world? If the latter then it is likely getting confused and/or showing misleading information. The MAC addresses *will* be unique so keep persisting... Yeah I detect router / switch are getting confused . But even powering off one pi . Reboot router / switch still shows same MAC address on different pi ! ? Edited November 25, 2021 by pocster Link to comment Share on other sites More sharing options...
Pocster Posted November 25, 2021 Author Share Posted November 25, 2021 17 minutes ago, SteamyTea said: what sort of Pi is it, then if I have one similar on my network, can see if it is the same as mine. It was a zero - though I have all variations ?? Link to comment Share on other sites More sharing options...
MJNewton Posted November 25, 2021 Share Posted November 25, 2021 Does the router allow you to enter the MAC addresses manually? What router is it? Link to comment Share on other sites More sharing options...
SteamyTea Posted November 25, 2021 Share Posted November 25, 2021 3 minutes ago, pocster said: It was a zero Here is my MAC 00:e0:2d:1a:23:0a Link to comment Share on other sites More sharing options...
epsilonGreedy Posted November 25, 2021 Share Posted November 25, 2021 26 minutes ago, MJNewton said: How are you discovering the MAC addresses? On the Pi's themselves (running ifconfig or similar) or is it from the router's view of the world? If the latter then it is likely getting confused and/or showing misleading information. The MAC addresses *will* be unique so keep persisting... I thought the MAC address was fused into a network chip at fabrication time so could a procedural error in the fab plant cause this problem? 1 Link to comment Share on other sites More sharing options...
MJNewton Posted November 25, 2021 Share Posted November 25, 2021 They're all going to be different, otherwise you wouldn't be able to use them on the same network. Link to comment Share on other sites More sharing options...
Pocster Posted November 25, 2021 Author Share Posted November 25, 2021 Just now, MJNewton said: They're all going to be different, otherwise you wouldn't be able to use them on the same network. Yeah I know - but something is confused Link to comment Share on other sites More sharing options...
Pocster Posted November 25, 2021 Author Share Posted November 25, 2021 2 minutes ago, SteamyTea said: Here is my MAC 00:e0:2d:1a:23:0a Same as mine ?????? Link to comment Share on other sites More sharing options...
MJNewton Posted November 25, 2021 Share Posted November 25, 2021 Just now, epsilonGreedy said: I thought the MAC address was fused into a network chip at fabrication time so could a procedural error in the fab plant cause this problem? In theory, I suppose anything is possible. In practice it's not going to be the case. Occam's Razor suggests it is almost certainly a router issue, not least given the majority are built down to a price and are full of bugs. Link to comment Share on other sites More sharing options...
epsilonGreedy Posted November 25, 2021 Share Posted November 25, 2021 1 minute ago, MJNewton said: In theory, I suppose anything is possible. In practice it's not going to be the case. Occam's Razor suggests it is almost certainly a router issue, not least given the majority are built down to a price and are full of bugs. Ok. I will stick to my specialist subjects namely software and climate change science. Link to comment Share on other sites More sharing options...
SteamyTea Posted November 25, 2021 Share Posted November 25, 2021 6 minutes ago, pocster said: Same as mine Here is the address on another one, but an old one. b8:27:eb:2c:9d:dd Link to comment Share on other sites More sharing options...
MJNewton Posted November 25, 2021 Share Posted November 25, 2021 7 minutes ago, pocster said: Same as mine ?????? In case you were being serious there (hey, you never know! ;-)) are there any similarities between your setups e.g. same OSs, perhaps one built the Pis for the other etc? MAC addresses can be changed and it might well be the case that your OSs are changing them (to a fixed value, which is a bad idea). Link to comment Share on other sites More sharing options...
Pocster Posted November 25, 2021 Author Share Posted November 25, 2021 5 minutes ago, SteamyTea said: Here is the address on another one, but an old one. b8:27:eb:2c:9d:dd Same as mine ???? ( I am joking btw !!! ) 1 Link to comment Share on other sites More sharing options...
MJNewton Posted November 25, 2021 Share Posted November 25, 2021 I'm Brian! (And so if my wife!) 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted November 25, 2021 Share Posted November 25, 2021 8 minutes ago, pocster said: Same as mine ???? ( I am joking btw !!! ) You can still use and abuse my MAC, just wipe it clean after. 1 Link to comment Share on other sites More sharing options...
Pocster Posted November 26, 2021 Author Share Posted November 26, 2021 (edited) This was driving me mad! So I boot 1 raspberry pi at a time. It gets whatever IP address the DHCP server decides. SSH into it and edit dhcpd.conf (I think ). Few lines to get it a fixed IP address ( for everything else I set the fixed IP off the MAC in the router - as it's simpler ). Have to do it this way - otherwise I can't tell what the hell's going on!. But as others have said all devices MUST have a unique Mac address when manufactured ..... Edited November 26, 2021 by pocster 1 Link to comment Share on other sites More sharing options...
Mr Punter Posted November 26, 2021 Share Posted November 26, 2021 Maybe you are just getting the MAC address of the router. Link to comment Share on other sites More sharing options...
SteamyTea Posted November 26, 2021 Share Posted November 26, 2021 Why not use a host name to SSH into. You can, if you want, give it a number. Link to comment Share on other sites More sharing options...
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