Feedback/questions on installing/using 18.06 on Raspberry Pi 3 (B model)

Hi everyone,

I am posting here after struggling for multiple days on getting OpenWrt to work on my Raspberry Pi 3 (B model). Basically, we moved and our usual router (TP-Link WDR3600 running OpenWrt) is gone and I thought this was a great opportunity to run OpenWrt on the Pi as a temporary router in the meantime (I have a serial line available all the time on it).

The Pi sits (as did our router) behind an Arris Surfboard SB6121 DOCSIS 3 cable modem. The cable modem is a blackbox to me but I think it acts as a bridge since the machine connected to it gets a public IP address like 73.15.XX.YYY (same as returned by ipecho dot net).

I flashed openwrt-18.06.2-brcm2708-bcm2710-rpi-3-ext4-factory.img on the device and could successfully start the radio and connect to LuCi over both Ethernet cable and wireless.

The issues started when I tried to move eth from the standard configuration to share Internet access from the cable modem. I tried to do things via LuCI but I would get disconnected when splitting the eth0/wlan0 bridge or assigning eth0 to the WAN zone. The UI would freeze, the timeout would indicate something went wrong and it would try to rollback, leaving the config in a halfway state.

In the end, I could make things work (I am writing this post from my laptop connected to the Pi sharing its Internet connection) by following the instructions from https://forum.openwrt.org/t/single-port-devices-define-wan-port/3344/2 (thank you so much!)

So here are some bulk questions, I hope the information will be useful to others as well (let me know if you want this split into topics):

  1. Is using LuCI expected to work when doing such a bridge/interface reassignement for single port routers or is the commandline the thing to use here?
  2. LuCI shows that masquerading is not enabled whereas I read it needs to be enabled (cf various links on the forum, I can only put 2 in my first post) for instance?
  3. LuCI also shows that WAN is red (not up) whereas it is actually working.
  4. Is the issue w/ eth0 needing to be under a bridge applies to model B (and not B+), cf https://forum.openwrt.org/t/18-06-on-raspberry-pi-3-b/18670/8 ?

Thank you very much for your help on all this, and let me know how I can improve the docs if needed!

Vincent

When done in the right order and when you ensure that your PC can handle the network transition to the new network etc. properly, then yes.

Masquerading should always be enabled on the wan zone.

Red just happens to be the color assigned to the wan zone (as in danger). It bears no meaning wrt. connectivity.

Hi jow

Thanks a lot for your answer (and for your original post about the uci commands btw)!

When done in the right order and when you ensure that your PC can handle the network transition to the new network etc. properly, then yes.

Would you happen to have the right order for the steps to be done here so that the whole thing works? I could not find a satisfactory one in my case.

Masquerading should always be enabled on the wan zone.

I am probably wrong here but the LAN->WAN connection does not show masquerading enabled in my case, and yet I can access the Internet from machines connected to the router/Pi. Isn't it the connection/zone which should have it enabled?

Red just happens to be the color assigned to the wan zone (as in danger). It bears no meaning wrt. connectivity.

Thanks, this makes sense. Is there any documentation I need to read which mentioned that?

Thanks again for your assistance and help, as well as a big thank you to the whole OpenWRT community for this amazing product!

Vincent