The message body contains just been thrown in at the deep end in looking after our small corporate network. We have carried out some updates to hardware and currently have a 100mb leased line coming in to a Cisco ISR4331 router which was all provided by our ISP.     I then have the Meraki MX84 sat between the ISR4331 and our new Cisco SGP300-28PP switches. One switch has all our data traffic with AD / File Server and desktops etc and the other has our new IP Phones connected.   When setting up I wanted to split the VoIP and Data on to 2 seperate VLANs so fault finding etc is made a little simpler. Our old IT contractor setup the old network using a 0/16 subnet and everything went through the one subnet with no VLAN which made everything messy when you looked at our old firewall dashboard and our servers were all set to Static IP's withing this subnet.   Now the problem arises!   I can setup VLAN1 for Data using the following info in the meraki dashboard:   VLAN Name: DATA Subnet: 10.120.0.0/16 MX IP: 10.120.0.1 VLAN ID: 1 Group Policy: None as yet   This will save perfectly fine and work as required. However when I go to tad the VoIP VLAN using the following details I get an Subnet Overlap error when I save the config. However I can't see where the subnet overlap is   VLAN Name: VoIP Subnet: 10.120.1.0/16 MX IP: 10.120.1.1 VLAN ID: 2 Group Policy: None as yet   Weirdly if I change the subnets to 0/24 it works fine. As I said I am new to this so I am sorry if my question / problem is stupidly simple. If I can use the 0/16 subnets it would save a lot of time having to reconfigure the servers and avoid any connectivity issues to staff working in the office and over VPN.   I would ask our previous contractor but due to the nature of why we have dropped them I can't really go back to them.   Any help is welcome ... View more