IP dhcp conflict alerts

[PradnyaR]

I observed there are 2 switches in the network and all the ports of switch are tagged to vlan Native 1.Will it cause the IP conflict alerts in network 

[PhilipDAth]

As long as the trunk ports that connect to other switches and network equipment are configured the same way, this will not cause any issues.

[GIdenJoe]

The default switchport configuration is trunk native vlan 1, allow all.

Endpoints don't usually tag their traffic which means all your endpoints will be communicating in the same VLAN.

However because of the behavior of spanning tree it would be better if you change all the ports leading to endpoints from trunk native vlan 1 to access vlan 1.

[AYEN]

Hi @PradnyaR ,

     As best practice to must configure trunk on the connecting 2 switches and define what is the native VLAN that you might use and configure the allow VLANs on the trunk. And for all connection to the endpoint, you must configure the access VLAN. Trunk is the default config in all port it is because to avoid any unauthorized access to the port.

[BlakeRichardson]

As long as your client devices and switches all have unique IP addresses you should be OK. 

[PradnyaR]

what else should I check if I am continuously getting IP DHCP conflict alerts.

Also dns nameserver of vlan1(mgmt vlan) is set to "proxy to upstream DNS".

Shall I change that, will that help?

[kYutobi]

It’d also helpful to track down the devices involved in the conflict, identifying the MAC addresses can give you a clearer idea of what’s going on.

As for the DNS setting, switching from "proxy to upstream DNS" probably won’t fix the conflict unless there’s a specific DNS-related issue. It doesn’t hurt to test, but I’d focus more on the DHCP setup and device configurations.