Enabling DHCP reservation. Must I reset clients?

[iamgigglz]

I have a basic home network with about 30 client devices all currently using basic DHCP (the usual mix of computers, TVs, phones, smart home devices etc)
I'm going to be getting a new router today (Netgear RAX30) and would like to switch to using DHCP reservation for everything. Any caveats?

What I'm worried about is say device A current has IP 192.168.1.123, and on my new DHCP reservation I set up device B to use that IP address. Will there be issues? Should I power cycle the devices to force a refresh?

 

[Conan257]

Should be the case that once set up (which will require every device to connect to the router first) that they will be recognised by MAC address and supplied with their assigned IP address.

 

[Caged]

Set the reservations up and then just wait for the existing leases to expire and for clients to get a new address. I haven't seen stuff take a DHCP-allocated address without checking it's not going to conflict in a long time, though you can never be totally sure with some of the IoT garbage that is out there.

 

[The1nonly1]

Set your DHCP range on the new router from something like 192.168.1.100 to 192.168.1.255. Restart the router so everything gets a new IP address in that range. Then use anything from 192.168.1.2 to 192.168.1.99 as your static/reserved IP addresses. Restart the router once you have set them all and it'll have the new IP address.

 

[paradigm]

I’m not sure I’d move to reservations for EVERYTHING, that seems like a massive amount of administration for no real gain.

Reservations for devices that you are targeting traffic rules at, sure, or devices that you want on a consistent IP like a NAS, but everything seems a fruitless task.

What I would certainly do is put IoT devices (where possible) on their own subnet with the least required access between the two.

 

[Quartz]

I’m not sure I’d move to reservations for EVERYTHING, that seems like a massive amount of administration for no real gain.

I did this in an enterprise environment. It was necessary because some legacy equipment had odd interactions with DNS and up to that point we had needed to have static IPs for everything. I suggested DHCP with reservations for everything because it was much easier to manage those pseudo-static IPs centrally. It worked very well indeed and saved a lot of time and effort moving forward. Remember that DHCP isn't just about IP addresses: you can push to the client a lot more than just an IP address.

 

[paradigm]

I’m not saying there aren’t reasons to manage a full subnet of reservations, at work I manage many, for various reasons (though this technique will largely be replaced by NAC and dynamic access rules in the future), but at home, through a consumer router interface, that just seems overkill.