ELK M1XEP issues - any thoughts?

[RAL]

How about that.  Well I am as surprised as all the other folks on that thread.  Typically network adapter chips have a permanent ROM burned MAC with only fancy ones allowing that to be over-ridden.  Though I think even those still have a hard coded one hiding in the background when using mac spoofing.  It kind of defeats the whole concept of MAC to not have it hard coded.  Maybe Elk isn't using a NIC chip but rather firmware written onto a more generic chip to function as a nic.  I haven't looked up all the chips on the board to even have a guess, but somehow it wouldn't surprise me.
 
I especially like the badbadbad mac.  It's like someone was playing a joke.
 
Has anyone ever heard of this happening on something aside from an Elk XEP?  

 
I've never seen a device that changed its default MAC address before.  But I can see how it could happen in the M1XEP. 
 
At a company I used to work for, many programmers would write hex data such as 0xBAD, 0xDEAD, 0xDEADBEEF and 0xDEAF into memory as a signal the something went wrong.  Nice way to make it obvious to someone reading a memory dump.
 
For most Elk users, this isn't too bad a problem as long as you realize the address has changed and reconfigure things.  But in a situation where there are two or M1's, each with an XEP on the same network, what do you do when they both change to the same MAC address? Seems like you would need to send them back to Elk for repair (until the next time it happens).

 

[apostolakisl]

As you might imagine, I've never had two things with the same MAC before to see first hand what might go awry.  Certainly I see the problem if you are using dhcp, but would it be a problem if you used a static IP?  Thinking through it, the router needs the MAC when assigning an IP, but it don't think the MAC has anything to do with routing after that, correct?

 

[RAL]

As you might imagine, I've never had two things with the same MAC before to see first hand what might go awry.  Certainly I see the problem if you are using dhcp, but would it be a problem if you used a static IP?  Thinking through it, the router needs the MAC when assigning an IP, but it don't think the MAC has anything to do with routing after that, correct?

 
IP addresses are used for routing packet data from one network to another through a router.  But within a particular network (say your local 192.168.1.x LAN), the packets are delivered based on the MAC address.  If you have two devices with the same MAC address, but assign them different static IP addresses, the ethernet switch they are connected to will still get confused about which one it is supposed to deliver data to. 
 
For example, say device1 sends a packet to the switch using port1 and out into the cloud and expects a response in return.  But before the response arrives, device2 sends a packet to the switch using port2.  The switch will see the duplicate MAC address and will update its tables to say the MAC address that was on port 1 is now on port2.  When the response to device1's request comes back, it will go to port2/device2 rather than port1/device1.
 
Many managed switches are smart enough to detect duplicate MAC addresses and disable the port that it finds a duplicate on.

 

[rkotara]

Usually, it seems that the MAC address switches to 00:40:9D:43:35:97 and the IP address becomes 192.168.3.64

 
Just had this happen to me.  I think a power event that happened a few days ago put it to this config.  I set my PC to the 192.168.3.1 address and told the RP software to connect to the device at 192.168.3.64.  Once it connected I changed it back to my desired IP but I have the same MAC as above now. I've never seen this before and I've had the system for many years.

 

[Madcodger]

Elk once monitored this forum very well, and replied almost daily. Can we now assume that is not the case? Do they monitor (or even still maintain, for homeowners), their own forum?