Bad IP Assingment

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Bad IP Assingment

We are having Bad IP Assigment for many of our Locations. We have contacted the ISP's and verified the IP information, the ISP had to clear the ARC file in order for the Meraki to accept the Static IP. The Meraki's will work fine and then the Bad IP Assignment Error comes back after a day or two. Is anyone else experiencing this issue or have any input? I am going to contact the ISP's again but want to see if anyone on here has some useful input.


Thanks in advance. Man Happy

24 Replies 24
Here to help

I would need to better understand how the AP's are placed in the network topology to be able to give advice on this. Usually, bad IP assignment is related to VLAN's on the ports where the AP's are plugged in or incorrectly configured DHCP to the AP's, however as they are set with Static IP's, I guess it's not DHCP.

The IP Assignment Error is on the Meraki Router (MX65w) not the AP. Please see below.




I have looked at that article already. We have over 2500 Meraki's in our Company and we have about 60 MX devices having the same  Bad IP Assignment Error. All of our Locations are connected to the modem via Static. The main provider that we are noticing that is giving us the main issue is Cox.

There is clearly some issue with ARP happening.


Lets check some basics.  Could you give me the IP address, subnet mask and gateway on the WAN interface on one device with a problem.  Please just put "x.x" for the first two octets to protect yourself.  So change to x.x.3.4/


Are the sites fed by fibre, or some other technology (such as bridged PPPoE)?

You are correct about the ARP issue, I have called the provider before to clear the ARP file and the Static starts working again but then it comes back after a day or two. 


Static IP =  xx.xx.217.138

Default Gateway = xx.xx.217.137

Subment Mask =


The Meraki Ignores the Static after showing the IP Error and gives me a DHCP IP of XX.XX.91.32


The connection is cable and they are not in PPPoe. 

Your static configuration is correctly aligned, no issues there.


I found other people with other types of kit having the exactly the same issue.

So I think it is a common issue with this ISP.


Perhaps we can solve this a different way.  Why do you need a static IP on the MX unit?  Why can't you use the DHCP assigned address?

I note that the Cisco cable kit also has specific ARP filtering available.  I wonder if your ISP uses this:

Have you tried contacting higher levels at your ISP to resolve the obvious issue on their end? If they're clearing out their ARP and everything is working fine until their ARP gets fouled up again, it's on their side.

And with 60 sites, I'd strongarm them to look into it or you'll move to another provider (have another provider ready as they may call your bluff).
Kind of a big deal
Kind of a big deal

First; is this happening on MX security appliances or some other Meraki device (and if so, what)?


Assuming it is an MX how do you connect to the ISP?  PPPoE?  DHCP?  Static IP?

Here to help

What version of firmware are you on?  I just upgraded to the latest 13.24 and am now seeing the same issue with my sites on Cox.  I did not see this issue previously when on version 12.24.  


I assumed this issue was fixed in this update but apparently not.


  • Resolved a case where MX appliances would not resume using their assigned static WAN IP address after a failover to DHCP occurred due to the absence of connectivity on the assigned static IP address

Hello All,


We are still having the same IP Error but we have found out that Cox is using older modems with older firmware that is causing issues with our Meraki Firmware. I am in the process of replacing the modem in one of our problem locations with a newer modem and firmware to see if that resolved the issue






The modem is not the issue, so don't waste your time. We have the same issue as well. Its only with Cox and no other ISP at this point. I don't know all the specifics but what I can tell you is that it has to do with Cox's legacy platform (not modem specifically) and the backend devices. This started happening with the upgrade to 13.x code MX since Meraki changed how the static IP is added to the device. Before in the 12 code it was all or nothing. Now in 13.x they have a series of checks that the MX goes through, one being the gateway ARP. On the legacy Cox code it doesn't respond to the gateway arp because of either a bug or something else and the Meraki checks fail.  This reverts it back to DHCP and gives you the "Bad IP assignment". Cox can clear the ARP on their end which allows the static IP again but since the gateway ARP check is still failing it gives you that alert still. If you were to change anything on the WAN IP page or reboot the MX it will cause it to fail back to DHCP and you will need to call in again.On Cox's new platform, the checks succeed so there is no issues. The only way right now to prevent the "bad IP" notice is to revert back to DHCP and stay there. This is what we did for the time being. Meraki Support is working with Cox and Cisco proper on a resolution. I ask for an update every other day and haven't got one yet. 

@BrianH Thank you for that information! 

Has anyone heard any updates on this issue?


I was hoping MX 13.27 would fix it, however it did not.

  • Corrected an issue that resulted in static IP addresses assigned to the MX WAN interfaces incorrectly failing back to IP addresses acquired via DHCP


I don't think Cox are very motivated to resolve the issue with their older devices.

Just curios if this has been fixed for anyone else or not.  I'm running MX14.19 and it seems to be working now at all my sites.  I'm assuming COX fixed something as I haven't updated for a while and it just started working at some point recently.    

We are still having the issue. We currently have 18 Locations with bad ip error. The device that gets the bad ip error is the MX and we have some Locations that are in bridge more. We also found out that its not just one provider having the issue but multiple. If anyone has found a fix, please share. The Meraki fimware updates have helped resolve most of our bad ip issues but we still have 18 Locations.



Building a reputation

So I have a few sites also with this issue. I had to call cox cable and a few other ISP providers to have them clear the arp table on the modem...


This happened right after Meraki MX firmware update was pushed to my MX65 devices 12AM EST 4/6/2018


Once the ARP is cleared on ISP side, the problem goes away and message is cleared on devices with statically assigned IP


i used 2  MX-65  at same time, one of them is ok, another one have BAD IP ASSIGMENT error, both are using same provider, i use them single in network and also together connect to same provider, all time are the same. both config are the same( off course different  static IP) but just one of them has this error.but its working, i can ping it .any solution ?

kav noroozi
Building a reputation

have you rebooted the carrier modem and the devices? 

Building a reputation

Should open a new ticket, this one is dead and buried back in 2017 lol.


That said if you change the Firewall and set the static IP you need to reboot the modem afterwards or it won't release the ISP DHCP IP it was assigned, only after the Meraki is static'd and the modem rebooted. Well that was my experience with Suddenlink

Here to help

Comcast replaced our cable modem today and since then our MX64 is showing this error and cameras behind the firewall are not reachable on the Internet any longer :Bad IP assignment configuration


Any ideas as rebooted the MX64 twice with no improvement.

Everytime I've had this issue the carrier has had to clear the arp cache on their modem.  Rebooting the mx breaks it again.

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