I am relatively new to this so fingers crossed you can help me!
I am trying to configure Internet access using a OpenWrt Combo of a Negear DM200 Modem and a Netgear R7800. I have installed OpenWRT v22.03.5 on both. I would like to configure this as shown below:
ISP > Modem DM200 OpenWrt 192.168.0.1> Router R7800 OpenWrt 192.168.1.1 >Devices
My ISP is NowTV uses DHCP client protocol over VDSL.
I have obtained the Client ID etc from my ISP router and have had success connecting to the internet via an older OpenWRT router.
Ideally i would like to be able to access the internet, prevent LAN leaking as being configuring a VLAN as suggested on the DM200 page and be able to access the modem through the router.
While you are asking for help in the very first sentence, I cannot spot a question in your post. Do you have a specific question?
Normal practise is to use DM200 in 'bridge' mode. Then configure DHCP client with the Client ID etc onto the R7800 openwrt 'router' etc.
The DM200 only has a single ethernet port, so makes it much more difficult to configure openwrt in bridge mode. Imho, you would be better off just using stock Netgear firmware on the DM200 in bridge mode! Openreach FTTC uses vlan tag 101.
Try searching 'DM200 bridge' on this forum for solution if you wish to try openwrt bridge mode. This thread may contain a solution using OpenWrt 19, as there is a reference to 'dsl0.101' (for Openreach FTTC).
Note OpenWrt 22 for DM200 will using DSA which uses different syntax in /etc/config/network file used in previous versions of OpenWrt.