[Dnsmasq-discuss] Incorrect broadcast address given

OB Lutz ob.lutz at gmail.com
Tue Oct 14 02:24:48 BST 2008

I'll get that output tomorrow. When multiple routers are in the
network, there will be routes to other sets of ips, like going out the wireless (ath0), but theres never another
route to A default route is only present when
another router is setup as an internet gateway. This output was from a
router isolated from the rest of the mesh network (it was on a
different wireless channel). The problem exists both when the router
is alone or when its talking to its brethren, so I chose the isolated
version to make everything as simple as possible.

On Mon, Oct 13, 2008 at 9:11 PM, richardvoigt at gmail.com
<richardvoigt at gmail.com> wrote:
> On Mon, Oct 13, 2008 at 2:23 PM, OB Lutz <ob.lutz at gmail.com> wrote:
>> My routing table:
>> # route
>> Kernel IP routing table
>> Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
>>   *      U     0      0        0 br-lan
>>       *            U     0      0        0 bmf0
>> Nothing ambiguous there. olsr adds routes going out the wireless
>> interfaces when appropriate. iptables just forwards olsr traffic
>> between wireless interfaces. Routes are clearly defined
> Not entirely sure, but I think your routing table is probably too
> complex for the "route" tool to handle, since it didn't find a default
> route or any external routes whatsoever.  Do you have the iproute2
> toolkit, can you use "ip route show" instead of "route"?
> Especially since you mentioned single-stepping through the dnsmasq
> code that sets the broadcast address and it matching on multiple
> iterations of the loop.  There's more going on than "route" is showing
> you.
>> On Sat, Oct 11, 2008 at 9:15 AM, richardvoigt at gmail.com
>> <richardvoigt at gmail.com> wrote:
>>> On Wed, Oct 8, 2008 at 1:41 PM, OB Lutz <ob.lutz at gmail.com> wrote:
>>>> The routing is fine. All the eth*s are bridged to br-lan, which is
>>>> given ( ath0 is,
>>>> ath1 iptables rules take care of forwarding
>>>> appropriate traffic around. Routing is not an issue.
>>> That's not fine.  Routing should never be done with iptables rules, it
>>> should be done with the kernel routing table.  And a particular subnet
>>> needs to correspond to a bridging (L2 forwarding) domain.  Right now
>>> your route to is ambiguous.
>>> Fix your IP address assignment and dnsmasq is going to work properly.
>>> Dnsmasq reads information from the kernel routing table, if you've got
>>> invalid information in there because you're overriding routing with
>>> iptables, you can't expect it to work.
>>> And as far as your thought that dhcp is dhcp and routing is routing
>>> and never the twain shall meet, the broadcast address is routing.
>>> Dnsmasq has to give it out.  So your nice idea of separation breaks
>>> down.

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