topic Re: DHCP Scope depleted via Syslog? in Network Platform API

DHCP Scope depleted via Syslog?

Prodrick — Tue, 28 Nov 2023 17:49:38 GMT

Who might be able or deny if Meraki MX make a syslog entry when either the DHCP Scope is depleted or when it cannot lease an IP to a client due to lack of available IPs?

I know there is an endpoint that provides this, but at scale it's too expensive to use against the Dashboard API rate limits.

Example API output. Can some provide a related event message example from the syslog?

Thanks so much.

Re: DHCP Scope depleted via Syslog?

Raphael_L — Tue, 28 Nov 2023 18:10:10 GMT

Hi,

Easy to test. Created a /30. Plugged a couple devices and captured the MX screaming these logs :

Done on MX18.107.6

Re: DHCP Scope depleted via Syslog?

sungod — Tue, 28 Nov 2023 18:14:59 GMT

I'd assume the "dhcp no offers" syslog event might also trigger. See...

https://documentation.meraki.com/General_Administration/Monitoring_and_Reporting/Syslog_Event_Types_and_Log_Samples

Re: DHCP Scope depleted via Syslog?

Prodrick — Tue, 28 Nov 2023 18:53:39 GMT

Thanks. Based on this I found the event.

Re: DHCP Scope depleted via Syslog?

Philip D'Ath — Tue, 28 Nov 2023 21:52:05 GMT

Also note that the "free count" that the API returns fails to take into account DHCP reservations. So it is very possible to have a "freeCount" and to have no DHCP addresses available.

You can test this easily by creating a DHCP scope, and then reserving the whole thing.

Re: DHCP Scope depleted via Syslog?

Prodrick — Tue, 28 Nov 2023 22:36:03 GMT

Thanks. This helps me to understand what I might be looking at where I'm seeing "dhcp no offers" in the syslog but the following endpoint shows a freeCount of 29.

https://api.meraki.com/api/v1/devices/[Serial]/appliance/dhcp/subnets

[{"subnet":"10.0.25.0/24","vlanId":0,"usedCount":224,"freeCount":29}]

I'm seeing this "dhcp no offers" event for the same mac address about every minute directly preceded by the following event types:

"wpa_auth"

"association"

"disassociation"

"association"

"wpa_auth"

"disassociation"