How to run a OpenWRT 23.05 loaded router downstream from a Comcast modem/router

Okay, so here goes...

I have put my Netgear C3000-100NAS Comsat modem (yes, I know it is old :( ) into "Router mode = no":

Then:

1) I tried to spoof the CM MAC of the C3000 onto the WAN port of the OpenWRT router, with the WAN port set to DHCP client (so Comcast would give OpenWRT an IP, I assumed). But even after some 30 minutes of having a cable plugging in between one of the LAN ports of the Netgear, and the WAN port of the OpenWRT router, I got no WAN IP:

2) Then I try to spoof the "Internet port" MAC of the C3000 onto the WAN port of the OpenWRT router, with the WAN port set to DHCP client. But even after some minutes of plugging a cable between one of the LAN ports of the Netgear, and the WAN port of the OpenWRT router, I got no WAN IP:

3) At some point in my testing, it seems that the C3000 provided a DHCP IP in it's default range (maybe when I left DHCP on before turning routing off, which I didn't think would make a difference), but still no routing to the internet through.

4) I have also tried: a) Unmanaged (no IP, no routing), and b) PPP (some error message about not being able to find signal on the line, even though it is a modem that is upline, right?). I also tried static address, which I realise now would never work.

I did try powering on both devices in different orders, and connecting them together at different times, as I read about MAC address leaking. No change in internet access.

I trust the issue is with settings on the OpenWRT side, because when I connect my PC to the C3000 in bridge mode, I get an internet IP address, and can browse fine.

What am I missing???? SO many hours spent thus far :(

Responses

BruceW

Gold Problem Solver

•

26.3K Messages

4 months ago

... I tried to spoof the CM MAC of the C3000 onto the WAN port of the OpenWRT router ...

I don't see how that would be helpful, and it might gum up the works. My advice would be to never assign the modem's MAC to any other device. Does keeping the router's native MAC not work?

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

1

U

user_hs5nwt

4 Messages

I guess I don't know enough about how a bridged device works in the context of a MAC based authentication system. I had assumed that as soon as Comcast saw the second MAC (first being the one that got the public IP from Comcast, being the C3000) it would gum up the works, to borrow a phrase. I did however try first without MAC spoofing, and I guess the missing step was to authorize (through the Xfinity app) the MAC of the Openwrt loaded device. Sound right?

(edited)

Like

Reply

4 months ago

0

Your Home Network

user_hs5nwt

How to run a OpenWRT 23.05 loaded router downstream from a Comcast modem/router

BruceW

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

user_hs5nwt

New to the Community?