My router does not let me disable DHCP! What can I do?

Some modems/routers from ISPs and some Apple devices make it really hard or impossible to turn off DHCP and/or DNS.

One alternative some of our users have found is to simply put a small/cheap router with NAT in between the modem and the rest of the network. That way you control what's inside via this router. The WAN side goes to the router/modem, and the rest of the network goes to what was before connected to the router.

A small downside is that port forwarding requires two forwards because there are two NATs. Now, if the router/modem has a setting for doing DMZ ... you can find what the WAN side port got for an IP (connect a laptop directly to the modem or the router), and hit the admin page, the status will tell you.

Once you know the IP of the WAN port _in the router_, not the modem, set that to DMZ in the modem.

WAN side of the modem or cable coax
     |              LAN port of the modem (e.g. 192.168.0.*)
     |              WAN port of the router
 [router]          e.g. ddwrt, with NAT
     | | |
     | \ \
     |  |  \

  rest of your network ... e.g. 10.10.10.* or 10.1.1.* to keep your sanity

Updated over 3 years ago

Back to the FAQ