open dd-wrt : WAN address assigned, no internet

Question

I have a linksys WRT1900 flashed to DD-WRT 3.0-r30796 and I am trying to connect it to a comcast modem/router to act as a DHCP for LAN. When using DHCP for WAN I am assigned an address (10.0.0.2) from the gateway at 10.0.0.1 (I cannot disable DHCP for the comcast modem/router). The dd-wrt router is hosting DHCP from 10.0.10.1 but there is no internet. I am not able to ping google.com. I have my dd-wrt in router mode.

I have set 10.0.0.1 as the gateway, and 75.75.75.75 as the DNS. What have I misconfigured that is preventing me from reaching the internet? From the comcast router page I can see the dd-wrt router connected.

Answer 1

Before anything I want's you to reset your DD-WRT setting by 30-30-30 reset

NOTE: When you flash your router it's recommended to give it Hard reset to clean your NVRAM from old firmware files, be careful and read their documentation slowly.

Lets say comcast LAN IP "192.168.1.1"

1. Make you DD-WRT router LAN IP "192.168.1.2"
2. Subset Mask "255.255.255.0"
3. Gateway "192.168.1.1"
4. DHCP server "enable"
5. DNS "192.168.1.1"

6. Now from comcast don't disable DHCP! just give your dd-wrt a static IP.

7. Restart you comcast, wait 2 min, then restart ddwrt and wait 2 min.