Duet Wifi's IP address changing mid-print

  • My router's been consistently assigning my Duet Wifi the IP address of for the last 6 months or so. I don't have a firm rule for it in my router, but I guess the router keeps the assignment in a cache or something.

    For the last week or so, probably coincident with one of my Duet firmware updates, I've been noticing this: I'll start a print with Duet at the usual I'll check on the print some minutes or hours later, and I can't connect. I look at my router and see my Duet is now at I point my browser to that address and everything works great, until I reboot or cycle power, in which case it goes back to This doesn't happen every print, but it has happened 5 or 6 times over the last week, and each time it switches to I haven't updated or changed the settings on my router's firmware (DD-WRT) recently (last time was probably 9 months ago).

    My config.g:

    M552 S1 ; Turn network on (can't seem to assign IP address)
    M554 P192.168.1.1	; Gateway
    M553 P255.255.255.0 ; Netmask

    Current firmware:

    Firmware Electronics: 	Duet WiFi 1.0
    Firmware Version: 	1.20.1RC2 (2018-01-01)
    WiFi Server Version: 	1.20+1
    Web Interface Version: 	1.20-RC3

    Any ideas? I might be able to fix it by adding a rule to my router, but thought I'd bring it up in case it's a problem for others as well.

  • administrators

    I can only think of 2 reasons why it should be changing between 2 IP addresses:

    1. A bug in your router;

    2. A fault in the WiFi module that is causing it to return 2 different MAC addresses.

    I suggest you check your router's status page to see what MAC address it thinks the Duet has, when it has each of those IP addresses.

  • Check the DHCP lease time. Increase it to more than a day. Maybe even a week if you want stuff to keep their ip addresses.

    If you got a very short lease and the duet gets unresponsive for some reason and does not ask for the same IP if lease is expired… it can get another address.

    For any equipment you want a static address set it as a static address 🙂

  • I made the IP address for the Duet "reserved" on the router so it always gets the same one.

    The default lease time for my particular router is 120min, but there is no "standard" really.

  • Oops - forgot about this thread. Thanks for the suggestion.

    I was wrong in my original statement - turns out I did have the address reserved for my Duet's MAC address in my router. I verified that when the router changes the Duet's IP address, the Duet's MAC address stays the same (as you'd expect). No idea why my router is changing the IP address…

    In any case it looks like the Duet has been eliminated as a suspect!

  • administrators

    You could give the Duet a fixed IP address in the M587 command.

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