Accessing ISP modem through OpenWrt router

Installing and Using OpenWrt
1

Hi all,

I've got a pretty vanilla setup, but I can't seem to get this to work.
I've a ISP router configured in bridge mode, connected to the WAN port of my OpenWrt Router. My openwrt wan interface gets assigned a public ip and the openwrt is on 192.168.1.1 and servers ips via dhcp to all my devices on 192.168.1.X.
I wanted to access the ISP router web interface, so I changed its address to 192.168.100.254 (by default it's on 192.168.1.254) and followed the guide here:

However I can't access the ISP router web interface. It doesn't even reply to ping from the openwrt router terminal.
I can access the router if I set a static IP on my laptop on the same range as the ISP router and connect to it with the cable directly, though. I must be missing some setting but don't know which. Any hint is appreciated.

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root@OpenWrt:~# ip route show
default via <redacted> dev eth0.2  src <redacted>
<redacted> dev eth0.2 scope link  src <redacted>
192.168.1.0/24 dev br-lan scope link  src 192.168.1.1
192.168.100.0/24 dev eth0.2 scope link  src 192.168.100.10
root@OpenWrt:~# ping 192.168.100.254
PING 192.168.100.254 (192.168.100.254): 56 data bytes
^C
--- 192.168.100.254 ping statistics ---
1 packets transmitted, 0 packets received, 100% packet loss
root@OpenWrt:~#
2

Hi

you could try to stop WAN & WAN6 interface
leave only MODEM interface UP
then power off/on the ISP modem

3

Thanks for the tip, but no go :frowning:

Anyway, I connected the cable on the ISP router side to another port and it works ok. Seems that the issue is with that specific port, but to use the bridge it has to be on that specific one. I guess I'll just have to connect another cable to one of the other ports for the ISP web interface :man_shrugging:

4

Perhaps this will help. For your modem interface use the following definition:

config interface 'modem'
       option proto 'static'
       option defaultroute '0'
       option device '@wan'
       list ipaddr '192.168.100.10/24'

After these changes restart your network or reboot the router. Good luck!

5

Thanks, also gave it a try and didn't help either.
I ended up just plugging another cable and setting up a switch port on the OpenWrt router for the 196.168.100.xxx network. It's uncool but seems to work fine.

6

What a pity.

I've noticed different behaviour of routers operated in bridge mode: some need a second interface with option device '@wan' and some others do not. :unamused: