[Dnsmasq-discuss] bug: trunk DHCP offer/replies being ignored by some devices

[Simon Kelley]

I just reverted the guilty change, so 2.77 should be OK now.


Cheers,

Simon.

On 08/04/17 00:55, Pedro MG Palmeiro wrote:
> The latest firmware for the printer is from 2015. This is one of those
> shared Epson/Fuji/Xerox models which I believe is entering EOL, since
> there is already another printer
> called M200 (Ecotank). Anyway, I'll report it.
> 
> Should the the implementation be correct in dnsmasq, then there will be
> more reports of this behavior from gateways implementing it, and that
> may move Epson into action.
> 
> Adding a mac exclude switch to dnsmasq is just marginally better than
> setting the printer IP manually, since both require intervention per device.
> 
> A switch disabling the whole implementation, or making it optional, thus
> reverting to the old behavior would be better if feasible, but I don't
> agree with removing it completely.
> 
> If nothing can be done, or be deemed unfeasible to be done, my opinion
> is that not much harm is done, since there is a way of getting things
> working (manual IP).
> 
> So, for me (3) it is.
> 
> Cheers.
> 
> On Fri, Apr 7, 2017 at 11:00 PM, Simon Kelley <simon at thekelleys.org.uk
> <mailto:simon at thekelleys.org.uk>> wrote:
> 
>     On 06/04/17 14:01, Pedro MG Palmeiro wrote:
>     > Dnsmasq trunk replies are being ignored by some devices, in my
>     case, two
>     > epson printers (AL-M200).
>     > Dnsmasq 2.76 works fine.
>     >
>     > This could be related with
>     > http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit
>     <http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit>;
>     > =88a77a78ad27adc3ed87b7ee603643d26cb896ee
>     >
>     > Please refer to
>     > https://bugs.lede-project.org/index.php?do=details&task_id=673
>     <https://bugs.lede-project.org/index.php?do=details&task_id=673>
>     > for tcpdumps.
>     >
> 
>     But RFC 6842 assures us that no clients are broken by this change :)
> 
>     The options here, as I see it are
> 
>     1) revert the change and don't support 6842
>     2) provide a way to disable the client-id reply for broken clients.
>     3) provide a flag to disable the client-id for all clients.
>     4) make the new behaviour optional, and provide a flag to enable it.
>     5) declare it No Our Problem and get the broken clients fixed.
> 
> 
>     5) is possible - have you talked to Epson? the AL-M200 looks like a
>     current product, and likely has field-upgradable firmware.
> 
>     1) is not attractive.
> 
>     2) may be possible. There is already a config option to tell dnsmasq to
>     ignore _incoming_ client-ids for a particular client, that could be
>     extended to apply to _outgoing_ cones too.
> 
>     Specifically, you'd need to add something like
> 
>     dhcp-host=<MAC address of printer>,id:*
> 
>     to turn off this for just those machines.
> 
>     4) is not attractive.
> 
>     I'm interested in peoples opinions; a flag to kill the new client-uid
>     behaviour globally, or just for particular MAC/IP addresses, or based on
>     a tag?
> 
>     A pity, the original patch was so simple.......
> 
>     Cheers,
> 
>     Simon.
> 
> 
> 
> 
> 
> 
> 
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> 
> 
> 
> 
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