Networking – Cascading Routers (LAN to WAN) and DNS

dnsnetworkingrouter

I live in a shotgun style house and thus am required to have to wireless routers to reach every room.

  • The first router is in my roommate's room and has an IP address of 192.168.1.1 with a DHCP pool of 192.168.1.2-192.168.1.150.
  • I have the first router set to use Google's DNS servers (8.8.8.8 and 8.8.4.4).
  • I am currently cascading my second router (ethernet runs from LAN on first router to WAN on second router).
  • My second router is set to a static IP of 192.168.1.2 (the MAC address of the second router is used to be sure the first router doesn't let any other devices use that IP address), and the gateway and DNS server is set to 192.168.1.1, the IP address of the first router.

Everything seems to be working fine, but I was wondering two things:

  1. Will my second router use Google's DNS servers that are set on the first router if my second router's DNS server IP address is set to the first router's IP address?

  2. Am I understanding correctly, by placing my second router's IP address in the DMZ of the first router, all ports will be forwarded to my second router?

Best Answer

  1. The second router will first check its cache for anything it gets asked by clients attached to it. If it doesn't know, it will query the first router. If the first router has it cached, it will reply with an answer, otherwise the first router will query Google's DNS for what it doesn't know and respond back to the second router with the answer.
  2. Different routers handle DMZ differently - it isn't always cut and dry. For the most part, only certain services are exposed (common ports such as 80, 21, 25, etc), so only a few ports will be opened up to the world, not all of them.
Related Question