[Cerowrt-devel] Replacing CeroWrt with OpenWrt - Routing

[Rich Brown]

Thanks Alan and Kevin,

This is helpful - I think I have enough to go on, and will report back/ask more questions as I move forward.

Best,

Rich

On May 13, 2015, at 4:07 AM, Alan Jenkins <alan.christopher.jenkins at gmail.com> wrote:

> On 13/05/15 02:19, Rich Brown wrote:
>> I am working to restore the functionality of my CeroWrt 3.10.50-1
>> router with an OpenWrt BB image.
>> 
>> Things are going pretty well, but I have run into a problem. In the
>> past, I frequently used two CeroWrt routers at my home: one was my
>> primary, and connected via PPPoE to my DSL link; the other was the
>> secondary, and used DHCP on ge00 to get an address from the LAN side
>> of the primary router.
>> 
>> My memory is that everything worked fine - I could connect to either
>> router's wifi, and get to things that were on the other router's
>> Wifi. (Bonjour/mDNS naming for example).
>> 
>> With OpenWrt as my primary router and CeroWrt as the secondary, I am
>> able to connect to the CeroWrt wifi and get anywhere - either the
>> OpenWrt subnets or to the Internet.
>> 
>> But connecting to the OpenWrt wifi, I cannot ping or telnet to any
>> addresses on the CeroWrt... What am I missing? (This is probably not
>> a deep question: I really don't understand linux routing
>> configuration...)
> 
> I can start with really basic :).
> 
> AIUI CeroWrt can do this using the babel mesh routing daemon.  That might be what you had working.
> 
> I don't know routing daemons, but I'm quite familiar with static routing, so in your shoes that's probably what I'd attempt first.  It at least gives you an idea what's going on at the IP level.  This would require... as a vague checklist, and being unhelpfully vague about wireless...
> 
> Second router:
> 
> 1) Make sure the LAN subnet (and IP address) doesn't conflict with the first.  I think CeroWrt already uses different addresses to OpenWrt. But for this example I use 192.168.16.0, netmask 255.255.255.0, and 192.168.16.1.
> 
> Wiki explanation of netmask:
> https://en.wikipedia.org/wiki/Subnetwork#Determining_the_network_prefix
> 
> 
> 2) a) Configure it with a WAN IP address that belongs to the first LAN.  Usually a static address, which is outside the DHCP pool.  Keep a note of all the static addresses you configure, to avoid conflicts.  b) Set default route to the first router.  OR make it a DHCP client which picks up the address and default route automatically.
> 
> You seem to have this part working, or CeroWrt wouldn't access the internet.
> 
> 
> 3) First router: set a static route for the subnet belonging to LAN2, which points at the LAN1 IP address of the second router.
> 
> You don't have this bit.
> 
> To add a separate routed wireless network on the second AP (as opposed to a more seamless one which allows roaming between the two APs): try configuring the wireless subnet adjacent to the wired one & use a single aggregated route for simplicity.
> 
> wireless lan: 192.168.17.0, 255.255.255.0
> 
> aggregated route for wlan + lan: 192.168.16.0/23, i.e. netmask 255.255.254.0
> 
> It could be extended to guest wireless as well.  Widen the route by another bit, and don't worry if you're not actually using the fourth subnet (192.168.19.0/24)
> 
> 
> 4) *** Make sure NAT is disabled on the second router. ***
> 
> I think you have NAT enabled on CeroWrt, because otherwise, without doing part 3), computers on CeroWrt network wouldn't get any packets _back_ from the internet.
> 
> 
> 5) Configure the firewall on the second router to accept all packets from the WAN interface / unknown networks.  You rely on the first router to do that instead.
> 
> 
> Alan