[Commotion-discuss] RPi Gateway

Josh King jking at opentechinstitute.org
Tue Mar 24 11:15:11 EDT 2015


Hi Josh,

The nodes don't actually propagate DNS information on their own. Rather
than using the DNS server that is passed by the DHCP lease, it uses one
which is statically configured for that network profile, unless it is
overridden (which is what is being done in part 2 of the instructions).
Without that being overridden, by default the nodes use 208.67.222.222
(an OpenDNS public server) as their upstream DNS server for things not
on their local domain (.mesh.local).

The captive portal included on the node runs on each individual node and
so uses the node's own local DNS server (which in turn uses the IP
address above for upstream queries). Part of configuring the nodes to
use a different, centralized captive portal or access management
solution would presumably could involve configuring them to use one or
more DNS servers provided by the centralized captive portal/access
management server, much as those are being configured above.

DNS servers can also be configured through the 'advanced' GUI interface,
and in a large deployment one could create custom images that pre-load
that information. So there are methods one could use to streamline the
process somewhat.

Does that help answer your question?

On 03/24/2015 12:45 AM, Josh Harle wrote:
> Hi Josh,
> 
> That's a nice sanity check for me, but I'm wondering why you need to do
> the stage "Changing DNS server information on each node" at all?  
> 
> Why when you use one or multiple internet gateways is it happy to
> propagate DNS through it, (without individually configuring nodes) but
> not if we set up our own DNS server?  Also, presumably this is what
> happens if we use a captive-portal/access management tools?
> 
> 
> 
> Kind Regards,
> 
> Josh Harle
> BSc (Hons) BA BFA PhD
> ____________________
> http://joshharle.com
> http://tacticalspace.org <http://tacticalspace.org/>
> ph: +61 (0)491 155 985
> 
> On 24 March 2015 at 02:15, Josh King <jking at opentechinstitute.org
> <mailto:jking at opentechinstitute.org>> wrote:
> 
>     Hey Josh,
> 
>     Funny you should ask, we just published documentation covering this use
>     case!
> 
>     https://commotionwireless.net/docs/guides-howtos/local-applications/hostnames.html
> 
>     Option #2 is what you want. It's not as thoroughly tested as we'd like,
>     so we'd appreciate your feedback (or any issues filed against
>     https://github.com/opentechinstitute/commotion-docs, the repo for the
>     website). The upshot is that you have to point the nodes to use that as
>     their DNS server rather than whatever their upstream DNS is.
> 
>     That said, I'm not certain why it would be dropping the gateway; that
>     could be a number of issues that we could delve into which are separate
>     from the DNS question.
> 
>     The round-robin bit isn't much trickier. In the section of the doc
>     entitled "Changing DNS server information on each node," you can add
>     multiple "list 'dns' '<ip address>'" lines, one for each server you've
>     set up. The node should just rotate through all available DNS servers
>     one at a time. There are some options to tweak its behavior as well, in
>     case it doesn't query them as expected.
> 
>     I hope this is helpful!
> 
>     On 03/23/2015 01:16 PM, Josh Harle wrote:
>     > Hi All,
>     >
>     > I have another question, which I'm sure people can give me insight on.
>     >
>     > In my mesh network, plugging into a router works fine, and we get the
>     > internet.
>     >
>     > I'd like to use an Raspberry Pi running dnsmasq to resolve all DNS
>     > queries to itself, and serve up some content.  Just like a captive
>     > portal really, but with the mesh in between.
>     >
>     > When I first connect it, the mesh node connected to it picks it up
>     as a
>     > gateway.  The DNS isn't being served through it though, and I can only
>     > connect to it via its IP address.  After a while the node no longer
>     > shows itself as connected to a gateway.
>     >
>     > What's the difference between it and a normal gateway?  What do I have
>     > to do to get DNS served up through it across the network?
>     >
>     > For bonus points, how much trouble would it be to put more than
>     one RPi
>     > into the network at different points to spread the load and reduce
>     > latency across a geographically spread network?
>     >
>     > Thanks for being awesome, in advance!
>     >
>     >
>     >
>     > Kind Regards,
>     >
>     > Josh Harle
>     > BSc (Hons) BA BFA PhD
>     > ____________________
>     > http://joshharle.com
>     > http://tacticalspace.org <http://tacticalspace.org/>
>     > ph: +61 (0)491 155 985 <tel:%2B61%20%280%29491%20155%20985>
>     >
>     >
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>     >
> 
>     --
>     Josh King
>     Lead Technologist
>     The Open Technology Institute
>     http://opentechinstitute.org
>     PGP Fingerprint: 8269 ED6F EA3B 7D78 F074 1E99 2FDA 4DA1 69AE 4999
> 
> 
> 
> 
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-- 
Josh King
Lead Technologist
The Open Technology Institute
http://opentechinstitute.org
PGP Fingerprint: 8269 ED6F EA3B 7D78 F074 1E99 2FDA 4DA1 69AE 4999

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