ePMP 3.5.1 to 3.5.6 FW / DHCP Reservation Issue

I am having a problem with all devices Force 200, 180, or Elevated with a static DHCP set on 3.5.1 FW after upgrading to 3.5.6 (with a static DHCP reservation) the CPE does not pass traffic until the DHCP is removed. Why is this happening? Thank you!

First image is before removing DHCP reservation. Second image is right after I remove it and the customers gets internet access instantly after the router pulls a new IP. It should have done it on a power cycle but after cycling the router first with no sucess then cycling the radio still didnt work. 



Hi Dillon,

Please let us to reproduce the issue and come back to you. For now it sounds like a defect, but we need to confirm it first.



Hi Dillon,

I was not able to reproduce your issue on my setup.

Can you please share with me device configuration sample of one of your CPE devices?

You can get it at Device GUI -> Tools -> Backup/Restore -> Backup Configuration -> Text (Editable).
Please send it to artem.grabenko at cambiumnetworks.com

Thank you,


Will do. Thank you!

Hi. We tried to reproduce the same in our lab several times with your configuration and everything is working as expected. Firmware 3.5.6. IP is assigned as set on GUI.

Maybe there is another host with the same IP already exists in the network and this makes the switch without IP.


We have 2500+ epmp clients and have had this issue dozens of times and find it is still occurring, so it is not just an issue at time of firmware upgrade.  When it happens you can resolve it by removing the dhcp reservation.  The arp entry in monitor->network then immediately updates with the correct MAC address.  Can then add the identical dhcp reservation with the same mac/ip back in.

I found the following in the system log of hte most recent occurrence.

Sep 1 00:00:35 8997- RWSD#4 dnsmasq[3605]: junk found in command line
Sep 1 00:00:35 8997- RWSD#4 dnsmasq[3605]: FAILED to start up

This was the reservation portion of the config file.

"dhcpLanHostTable": [
"dhcpLanHostIP": "",
"dhcpLanHostName": "Managed Wifi",
"dhcpLanHostMAC": "64:D1:54:E5:25:64"

Paul Beverage

VP of IT

So this happens not all the time? How often this happens on your network? 

The log is showing that this happened 35 seconds after the device was booted.

Does it always happen after boot? What was the PPPoE status during the issue?

Can you take a tech support file from the SM then this happens next time and send it to me?



So after testing I am able to confirm that the issue is caused by a space in the DHCP Reservation "Name" Field. In Firmware Version 3.3 you are able to put a space in the Name Field and after 3.3 you are not allowed to. But if you upgrade from 3.3 to v3.5.1, v3.5.2, or v3.5.6 then it automatically keeps the same values as what was previously there. If I remove the space the router connects back with the same IP that was specified in the DHCP Reservation within seconds and I have internet access as well.