Move DNS & DHCP from ISP router to Lede router

Installing and Using OpenWrt Network and Wireless Configuration
1

Like to use my Lede router as DHCP&DNS server in my network iso the the flaky one in the router of the ISP

My setup:
An Experia V10 router provided by the ISP (KPN).
From its LAN connections I have 2 routers connected, a TPLink WDR3600 and a TPlink C7
I need all 3 routers to have sufficient WiFi coverage

Like to have:

  • One network segment throughout the house
  • Moving around in the house should not alter the IP address
  • Have DNS working for the internal and external network
  • No double NAT so I can use UPNP to open ports on the V10 from any device in the network

The most obvious configuration is to use the DNS & DHCP of the V10. However it is flaky, after a reboot it does not known the host names of the devices in the internal network and it only allows for 10 static IP addresses. So I was thinking to use the DNS & DHCP of the WDR3600, where I have already Lede 17.01.4 on.

Steps I did:
Connect V10 LAN to WAN of WDR3600
Connect LAN of WDR3600 to computer which I used to configure the routers
Disable DHCP on the V10
Static address on the WAN of the WDR3600, in the address range of the V10 LAN
from SSH on the WDR3600, I can still ping outside servers

Where I run into trouble is:

  • how to bridge WAN and LAN and WiFi of the WDR3600
  • setting up the DNS & DHCP on the WDR3600

Any suggestions, I would highly appreciate

2

It's a matter of changing the VLANs in the switch configuration. Alternatively you can leave the WAN port empty for now and use the LAN ports only on the WDR3600.

You need to configure a custom DHCP option since the clients need to use V10 as default gatway. Add "3,x.x.x.x" to DHCP-Options in DHCP Server Advances Settings on the LAN interface. Where x.x.x.x is the LAN IP address of V10. (DHCP Option 3 is default gateway/router address.). You also need to configure custom DNS servers on the LAN interface. Use you ISP's or for example, 1.1.1.1 and 1.0.0.1, 8.8.8.8 and 8.8.4.4, or 9.9.9.9 and 9.9.9.10.

3

When supplying a dedicated DNS server in advanced options of the LAN interface, like 6,8.8.8.8, there is no DNS inside the network. So local device names are not resolved anymore since the request directly goes to the 8.8.8.8 DNS server. How to correct that?

4

Actually I was thinking of the setting "Use custom DNS servers" on the LAN interface. It should allow you to resolve local device names.

5

Thanks Mikma,
It worked out:
*connecting V10 to the LAN port of the WDR
*Fill in "custom DNS server" field: 8.8.8.8 in the LAN interface setup
*Also added 8.8.8.8 to "DNS forwardings" in the DHCP setup, do not know if it is necessary
now the network is aware of both internal IP addresses and external.