Posted: Wed Jan 10, 2018 8:49 Post subject: Combining modem/router (non-DDWRT) with DD-WRT router
For my internal network at home, I require that IP addresses of my devices don't change (home automation purposes). Unfortunately, the modem/router provided by the ISP (sagem) does not allow that. Therefore I got hold of a second router (no modem): Linksys E1200. I installed DD-WRT (v3.0-r29519) on the Linksys. Both routers are placed right next to each other.
My question is: what should be the basic setup for connecting the two, and having the Linksys DD-WRT router provide the IP addresses rather than the sagem. I guess this means basically considering the sagem as a modem rather than a modem/router.
Reading quite a bit on different setups of routers and modems (including these forums), this leaves me a bit flabbergasted, unfortunately. (Access points vs bridges vs ...; local IP vs WAN IP; can the dd-wrt router still get an IP address if DHCP on the first router is switched off; etc.)
Could someone indicate how to set such system up?
--internet----[sagem modem/router]----[dd-wrt router]
| | |
| | device C
| device B
Posted: Wed Jan 10, 2018 10:32 Post subject: Current settings on the dd-wrt router
At the moment the wire from the sagem modem/router goes into one of the 4 ethernet connections in the dd-wrt router instead of the into the single "internet"-labeled jack. These are the current (I think relevant) settings on the dd-wrt router:
* Setup -> Basic Setup
* Connection type: disabled
* Router IP
* Local IP address: 192.168.1.100 (because DHCP server on sagem IP range ends at 63)
* Subnet mask: 255.255.255.0
* Gateway: 192.168.1.1 (= IP of sagem modem)
* Local DNS: 192.168.1.1 (idem)
* Network Address Server Settings (DHCP)
* DHCP Type: DHCP Server
* DHCP Server: Enabled
* Start IP address: 192.168.1.101
* Static DNS 1: 192.168.1.1 (= IP of sagem modem)
* other static DNS: all 0.0.0.0
Note that the cable from the modem/router attaches to a LAN port on the dd-wrt router, not the WAN port! (otherwise the below does not work...)
On the dd-wrt router:
Configuration on the dd-wrt router
WAN Connection Type
Connection type: PPPoE
Username: <username provided by ISP>
Pwd: <password provided by ISP>
Local IP Address: 192.168.1.1
Subnet Mask: 255.255.255.0
Local DNS: 192.168.1.1
Network Address Server Settings
DHCP Type: DHCP Server
Start IP Address: 192.168.1.2
Static DNS 1: 220.127.116.11
Static DNS 2: 18.104.22.168
Physical Interface wl0
Wireless Mode: AP
Wireless Network Mode: Mixed
Wireless Network Name (SSID): dd-wrt
Wireless Channel: Auto
Channel Width: 20 MHz
Wireless SSID Broadcast: Enable
Network Configuration: Bridged
The WAN IP of the dd-wrt router is an external IP, which shows that the bridging of the modem/router works, I think.
The problem: although devices can connect through wifi to the dd-wrt router, it seems that the LAN ports do not work: devices connected to it do not get an IP number. Anyone any ideas on how to solve this?
It's because you LAN ports are most likely messed up in nvram values. In which case, one of the LAN ports is acting as a WAN port, the others won't work.
Do NOT set static DNS to google. Just leave it blank. It will use your ISP's DNS server (much faster). The router itself will act as a DNS forwarder. Add this line to services > dnsmasq options instead (although not strictly required):
That sets your router as the DHCP server for all your LAN clients.
See these articles to fix your port/vlan configuration:
A bit dated, so you'll have to improvise. Btw, it's possible to brick the router if done incorrectly. Leave wireless GUI access enabled (and setup wireless), so you can fix it if need be, otherwise you're gonna regret it.
I actually just got it running again... Indeed, connecting to WAN instead of LAN was necessary. Then the system stated to act really weird: the URL 192.168.1.1 in my browser would either open the router's page, or the bridged modem/router. That didn't make sense at all to me...
One of the times that the admin page for the bridged modem/router I was able to switch of DHCP and wifi on that box. And lo and behold: I have access again...