Both modem and router have DHCP enabled? Can I turn off one DHCP server?

[3demons]

I don't know enough about this topic and am looking for help.

Here's the setup: I have a cable modem (ubee DVW326) connected to a router (Netgear r8000). Today I discovered that the DHCP server is enabled on both devices.

This is the Modem:

and this is the router:

my question is, do i need the DHCP on the modem active, or can i not just disable it? Do both need to be on? if so, why? My understanding was that you only needed one DHCP server per network, so if i had to choose one, I would make the assumption that since the processor on the router is more powerful, to leave DHCP enabled there instead of the modem.

I am only now diving into the networking portion of my very short I.T. career, so any explanation would be awesome, and please correct me if my views of info is flawed/simply-incorrect so that i can learn otherwise.

 

[Hlsgsz]

Teh simple answer would be that you gain a port by using yout router as a router adn having DHCP enabled. The alternative is to use the router as an access point. TO do that you have to plug the modem in LAN port and leave THE WAN port unused(basically the router becomes a switch with WI-fi).
As an alternative, many modems support going into "modem mode", witch makes them act like an older modem with no routing duties.

 

[nukemaster]

DHCP just assigns IP's to computers. It is not cpu intense, but you are 100% right that it is not required.

Your modem contains a router and this is why it is doing it.

I would guess your router has better performance for things like QoS and stuff so you can try with it off on the modem, but to be honest under normal use, you should not even see the modem unless you connected it to a lan port on the router instead of WAN.

 

[Hlsgsz]

A more in detail explanation is that you currently have two networks. One routed by your modem to witch you router is connected and one routed by your router that contains everything that's connected to it. As long as you keep this configuration, yes, you need the router;s dhcp enabled to serve ips to the devices on the second network. Using teh router as an access point as stated in my above comment would take all teh devices to teh modem's network.

 

[jsmithepa]

My understanding was that you only needed one DHCP server per network,

Correct. That assuming you have a single private subnet, which most people do.

Your post contains TWO subnets: 192.168.0.x and 192.168.1.x.

If all of your clients are in the 168.1 subnet then you can probably ignore the whole thing and nothing bad will happen.

You appear to be doing double-NAT (Network Address Translation), the "modem" is doing the first NAT and your router is doing the second NAT, again, as long as all of your clients are on the second subnet, nothing will happen. You will only run into trouble when you start to doing port forwarding, torrent etc.

For simplicity sake you should only do ONE NAT. The simplest way to do is to convert the router to an Access Point. There is a sticky on the Wireless section on how to do this.