[Dnsmasq-discuss] Incorrect broadcast address given

richardvoigt at gmail.com richardvoigt at gmail.com
Tue Oct 14 02:11:49 BST 2008

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

> 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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