Meraki L3 switch DHCP server stop working

[Abhay1267]

I am using Meraki firewall, Meraki L3 switch & Meraki AP. From last 6 months everything was working as expected. DHCP server was configured on Meraki MS250 switch and everything was working. 3-4 days back without doing any changes, this DHCP stop releasing ip address to wired/ wifi clients. few wifi clients are able to get the ip address randomly but most of them are not. This issue is happening with all the vlans. Working with Meraki TAC from last 3 days, but no progress. Can anyone help here pls !

[alemabrahao]

What version are you running? Have there been any firmware updates recently?

[Abhay1267]

Current version: MS 15.21.1

[alemabrahao]

Okay, have you tried version 16.7? What has support told you so far?

[Abhay1267]

I have scheduled this firmware upgrade for tonight and then see the improvement. Support team still taking packet captures only.

[alemabrahao]

If support hasn't been able to help so far, I don't think we can do much other than make suggestions, such as upgrading or downgrading the firmware.

Have you tried putting another DHCP server on the network? Just to validate if the problem could actually be something in the switch's DHCP?

[Abhay1267]

Yes, if i put another dhcp server in the network, it work.

[Abhay1267]

Done with upgrade but no luck.

[JacekJ]

I noticed a few days ago that the DHCP Servers page changed to the upgraded one in my env (now it has settings for v4, v6, and also RA guard).

Sounds like a very suspicious coincidence to me?

Double check the settings over there (switching -> monitor -> dhcp servers & arp).
Tried rebooting the MS250? Is it only one switch or a stack with L3?

[Abhay1267]

2 switches are in stack.

[GreenMan]

One suggestion:   make sure that, before you doing anything specific, you at least ask Support what they think of any additional / alternative steps you're thinking of making.   Also:  if you have an MX, why not do the DHCP there, instead of on your switch?

[Abhay1267]

I can change DHCP from switch to MX, but this is not the solution. Will try this on weekend

[PhilipDAth]

I've only had an issue when the system ran out of DHCP addresses.

You could try turning off DHCP, and then turning it back on again.  This should hopefully reset the DHCP sub-system.

You could try reducing the DHCP lease time in case it is a starvation issue.

[Abhay1267]

reduced lease time to 1 day. Also, 80% ip addresses are available in all the scope.