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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

14 REPLIES
Here to help

Re: Bad IP Assingment

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.

Head in the Cloud

Re: Bad IP Assingment

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?

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Re: Bad IP Assingment

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

 

 

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Head in the Cloud
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Re: Bad IP Assingment

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.

Head in the Cloud

Re: Bad IP Assingment

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 1.2.3.4/255.255.255.252 to x.x.3.4/255.255.255.252/

 

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

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Re: Bad IP Assingment

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 = 255.255.255.252

 

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. 

Head in the Cloud

Re: Bad IP Assingment

Your static configuration is correctly aligned, no issues there.

 

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

https://supportforums.adtran.com/thread/2021

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?

Head in the Cloud

Re: Bad IP Assingment

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

https://www.cisco.com/c/en/us/td/docs/cable/cmts/feature/cblarpfl.html

Here to help

Re: Bad IP Assingment

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).
New here

Re: Bad IP Assingment

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.

13.21

  • 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
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Re: Bad IP Assingment

Hello All,

Update

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

 

Cheers,

 

New here

Re: Bad IP Assingment

Hector,

 

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. 

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Re: Bad IP Assingment

@BrianH Thank you for that information!