4 replies to this topic

[VanKurt]

Hi there,

as of today DHCP suddenly stopped working on my Netduino Plus 2. I didn't touch the device in days, so the problem somehow occurred on its own ;-)

 

When I look at my router's web interface, I can see that the Netduino is trying to get an IP with a MAC address of "[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]00 04 A3 00 00 00[/color]". That is not the address on the board's sticker (and I did not configure it either). Of course the DHCP IP address mapping won't work with this wrong MAC address.

While searching the forum's I saw that the above mentioned MAC appears rather often when people are having problems. Where does it come from?

 

I tried two things to solve the problem:

• Re-set the MAC address via the MF Deploy Tool: The tool tells me that everything was written fine to the Netduino. When I disconnect it, and then reconnect connect it, I can read the previously made changes back without any problems. Although everything looks so good, the Netduino still appears with the wrong MAC ("[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]00 04 A3 00 00 00") when doing its DHCP thing with my router.[/color]
• [color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]Set the MAC in code while starting up: Although this sets the MAC correctly, other settings get messed up. For example the gateway IP is set to 0 (and can't be changed since it's read only). Thus DHC won't work.[/color]
• [color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]Restart the router and the Netduino a million times: no effect at all.[/color]

PS: I'm using a Netduino Plus 2 with 4.3 Firmware and an Arcor EasyBox router. As mentioned above this setup worked fine, until this MAC problem occurred today.

 

Can anyone help?

Thanks!

[Chris Walker]

Hi VanKurt,

 

We've seen this before, but haven't been able to reproduce it.  Do you know what's different today than yesterday, in terms of the app loaded onto the Netduino or your network router, etc.?

 

The MAC you're seeing is the default MAC address; it's written over by the Netduino's MAC in NETMF's ENC28J60 driver (read from flash).

 

We'd love to get to the bottom of this.  We just need to be able to reproduce it; then we should be able to fix it in the NETMF core.

 

Chris

[VanKurt]

Hi Chris,

thanks for your quick reply. Unreproducable problems are the best. I love them, too ;-)

 

To answer your questions:

I could swear I didn't change anything. The app flashed to the Netduino hasn't been changed for a few days. So has my routers configuration.

 

Maybe tomorrow I could completely erase and re-flash the Netduino using your 4.3-Firmare-Flashing-Guide. Do you think this might help?

[Chris Walker]

Hi VanKurt,

 

If you can, please erase and reflash the board.  Then enter its MAC address.  And see if the issue comes back.

 

If it does, we will have you image your board and then try to reflash one here.  If we can't repro the issue, WireShark is the next step.  But ideally we'll figure out a repro--so we can trace through the firmware and figure out how/where the MAC address settings are going awry.

 

Chris

[VanKurt]

Good news everyone^TM :

 

I did the following:

• Erase the board
• Flash the 4.3 Firmware
• Configure the MAC address
• Download my app

The great news: everything is back to normal! The MAC seems to have been persisted correctly, and DHCP is working again.

I just hope it stays that way ;-)

 

Thanks for your help.