RPi3 MAC Number

[Bill Arnold]

After much gnashing of teeth, days working with ugs, cncjs and bcnc, and some loss of sleep, I have a combination of apps on my RPi that are running consistently; more on that in another post.

The issue (condition?) that I'm trying to understand now is the MAC number.

I ran the commands to find the MAC number and got the following for the wifi link:

pi@RPi-LSR:~ $ cat /sys/class/net/wlan0/address
b8:27:eb:66:b9:da

pi@RPi-LSR:~ $ ifconfig wlan0
wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.0.105 netmask 255.255.255.0 broadcast 192.168.0.255
inet6 fe80::9625:1938:3572:2d51 prefixlen 64 scopeid 0x20<link>
ether b8:27:eb:66:b9:da txqueuelen 1000 (Ethernet)
RX packets 1099 bytes 111026 (108.4 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 981 bytes 173847 (169.7 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0


I also ran the commands to get the ethernet MAC, although it isn't used:

pi@RPi-LSR:~ $ cat /sys/class/net/eth0/address
b8:27:eb:33:ec:8f

pi@RPi-LSR:~ $ ifconfig eth0
eth0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
ether b8:27:eb:33:ec:8f txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

I setup my wifi router to assign a permanent IP as follows:
B8-27-EB-66-B9-DA 192.168.0.112 Enabled

However, when the RPi links to the router, this is what I get:
RPi-LSR 86-16-F9-66-B9-DA 192.168.0.105


Overall, it's more of a curiosity, I suppose. I can link to the two RPi boards I've set up by using the hostname I gave each of them.

What say you IT gurus?

 

[Brent Dowell]

Probably depends more on the router and firmware?

I just set the pi to use a fixed ip address and not use DHCP.

On my routers, I'm also able to let the device connect, and once it does from there I can make it static on the router.

It's also possible on the pi to 'set' the mac address. I wonder if there is something going on with the config somewhere where it changes from the default to something else?

https://www.raspberrypi.org/forums/viewtopic.php?t=171534

 

[Darren Wright]

I'm going to guess that you need to release that address (the 105 one) and then reconnect. There's probably a lifespace time-out assigned to it and it won't renew until that expires.

The other option would be to just use a static ip on the Rpi outside of your DHCP ip range.

 

[Bill Arnold]

I'm going to guess that you need to release that address (the 105 one) and then reconnect. ...

Tried that last night. One time it connected and got an IP ending in 109. Shut it down, let it release. When it attached the next time, it got the 105 address. The MAC number remained the same.