MS250, DHCP configuration, Page System, Multicast Issues.... maybe

[lmt737]

I recently replaced a Cisco 2960x that ran a DHCP scope on vlan 1 (flat network) and replaced with an MS250. I configured a DHCP scope on the MS250. Now I am getting reports that our paging system is ringing when an employee tries to page. My understanding is that when you create a DHCP scope on an MS250, the device does layer 3 routing. Is this correct and will I need to enable layer 3 multicast on this device ? 

[Mloraditch]

While your symptom is a bit odd, when I have issues with paging and multicast on meraki, I enable the IGMP snooping querier on the relevant vlan and leave IGMP snooping enabled for the vlan. You should only need actual multicast routing if your broadcast needs to cross subnets.

Overview of settings:
https://documentation.meraki.com/MS/Other_Topics/Multicast_Overview%2C_Configurations%2C_and_Best_Pr...

[PhilipDAth]

Enabling DHCP does not enable layer 3 routing.  What is your default gateway for your network?  If it is not the MS250 - you don't have an issue.

This document talks about enabling layer 3 routing.

https://documentation.meraki.com/MS/Layer_3_Switching/MS_Layer_3_Switching_and_Routing

@Mloraditch has posted a good guide about multicast.

>Now I am getting reports that our paging system is ringing when an employee tries to page.

Wouldn't this be expected behaviour?

[lmt737]

@Mloraditch has posted a good guide about multicast.

>Now I am getting reports that our paging system is ringing when an employee tries to page.

No, when paging you want to page not ring.

[lmt737]

Well, when the MS250 has a DHCP scope configured, you also have to configure an interface and static route. The interface is what the dhcp clients get and the static route is the route out to next hop. So dhcp clients get 10.10.10.2 as the gateway with a hop of 10.10.10.1. All static devices have a 10.10.10.1 gateway.

[lmt737]

We have a 10.10.10.1 for static and gateway out to internet. The DHCP scope uses 10.10.10.2. 

[lmt737]

Please disregard.

[lmt737 · Accepted solution]

the issue was not multicast at all. the page system had to have a settings change.