Most routers will balk if you attempt to assign WAN and LAN on the same subnet. Some will complain if you attempt to assign 192.168.anything to the WAN and LAN ports. Generally, I'll assign 10.something to one side and 192.something to the other side, but there are other choices. FIOS routers that I see default to 192.168.1.1. Comcast routers usually default to 10.0.0.1. I usually leave these alone because FIOS and Comcast support will assume these addresses. If your customer calls FIOS or Comcast support, one of the first steps will be to reset the router. If my network can use the default IP addresses, there is a good chance that the customer can at least use a browser, even if the control system can't tolerate the setup.

Lately, I've noticed that some of the ISP support staff will first check to see if their router default setup has been modified in some way, then avoid blindly resetting their router. This is a good development and suggests that I should change the default router subnet as a flag to support -- keep out or tread carefully.


The second router is a client of the first router. The first router is a client of a router at the ISP. For most purposes the second router is nothing special as far as the first router is concerned. Your LAN devices are clients of the second router and should use the second router as their gateway address. 8.8.8.8 and 8.8.4.4 are DNS servers at Google, not Gateways.