dd-wrt WAN setup

Sneezy_Squid · February 23, 2019

Hello out there.
Long story short. I bought a Netgear Nighthawk M1, to serve as a modem for my TP-Link Archer C7, flashed with dd-wrt (v3.0-r38840 std)

I do obtain a WAN IP, but there's still no internet.

IP passthrough and DHCP is disabled on M1
LAN settings on M1
Address: 192.1681.1

Subnet mask: 255.255.255.0

Settings on Archer C7
WAN connection type - Automatic configuration-DHCP
Local IP 192.168.2.1
Subnet mask: 255.255.255.0

Gateway: 192.168.1.1
DHCP Enabled
Operation mode set to Gateway

I have shuffled around with different ip settings, both for M1 and Archer, still no luck.
I do obviously miss something, but what

Best regards

Sneezy_Squid · February 26, 2019

On 2/25/2019 at 11:37 AM, PrinceNorris said:

Does that mean you have two router IPs?

Yep, my Netgear Nighthawk M1 have an ip, so do my TP- Link Archer C7

A quick notice. Ive flashed the C7 back to stock firmware. Everything is fine there. It all works. So i assume the stock firmware is autofilling some settings, wich i need to do manualy in dd-wrt.

Any guess?

Donut417 · February 26, 2019

1 hour ago, Sneezy_Squid said:

Yep, my Netgear Nighthawk M1 have an ip, so do my TP- Link Archer C7

A quick notice. Ive flashed the C7 back to stock firmware. Everything is fine there. It all works. So i assume the stock firmware is autofilling some settings, wich i need to do manualy in dd-wrt.

Any guess?

The issue is the M1 is essentially a modem/router so one issue you will run in to is double NAT, actually most LTE providers use carrier grade NAT which means you would run in to triple NAT, which means even if you could pass the internet along to the Archer C7, some device might have issues.

Id first see about putting the M1 in to bridge mode which makes it in to only a modem. Another issue you might be having is at least on TMobile you are using IPv6 a lot from what I read, so I know for a fact that DDWRT does NOT have auto settings for IPv6, I had to set that up manually when I was using DDWRT router with Comcast. You will have to see what IPv6 settings your ISP uses because there are at least 3 ways they can setup IPv6 on their network.

Sneezy_Squid · February 27, 2019

It's in "bridge mode already, by enabling IP-passthrough, and disabling DHCP (as netgear recommends to do)

We don't have TMobile in Denmark, and i'm am running IPV4.

If i connect my M1 directly to my pc, i can see a different IPV4 every past 24 hours or so, same goes for default gateway and DHCP server. But primary/secondary DNS stays the same.
You might be right on the NAT assumption. Subnet mask is 255.255.255.255 when directly connected, but my "mobile router setup) says 255.255.255.0.

But. I've played around with the settings, and maybe i'm on my way to figure it out. (Setup -> Basic setup -> Networking) there's a bunch of settings regarding internal hardware routing. I've come so far to directly passing everything through the C7. But when it's done, i cant connect to my C7, and there's no internet at wifi. So its just a direct route from WAN port to switch, not passing through the router part. Does it make sense?