[Dnsmasq-discuss] dnsmasq.conf 2.41 violates RFC-2132 ondhcp-option=47

[Data Control Systems - Mike Elkevizth]

Just to comment on this, which may or may not be relevant, I have assigned a
static IP to my one OpenSUSE 11 box.  It seemed to intermittently refuse to
accept a dhcp assigned address.  I would attribute this to a dhcpclient
problem with OpenSUSE rather than dnsmasq only because I have not trouble
with any other client.  This could be because the newer versions of
dhcpclient do things "the correct way", but the correct way in my opinion is
to work, which it most certainly does not.  And my dnsmasq config doesn't
have option 47 in it at all so that isn't causing the problem for me.

Mike E.


-----Original Message-----
From: dnsmasq-discuss-bounces at lists.thekelleys.org.uk
[mailto:dnsmasq-discuss-bounces at lists.thekelleys.org.uk]On Behalf Of
Simon Kelley
Sent: Thursday, September 04, 2008 8:51 AM
To: Matthias Andree; dnsmasq discussion list
Subject: Re: [Dnsmasq-discuss] dnsmasq.conf 2.41 violates RFC-2132
ondhcp-option=47


Matthias Andree wrote:
> Greetings,
>
> dnsmasq 2.41's .conf (I'm looking at Ubuntu 8.04 LTS installed from server
> CD, in case that matters) suggests to uncomment a line
>
> "#dhcp-option=47"
>
> in order to send an empty NetBIOS scope.
>
> However, if I do that, dnsmasq sends option 47 with zero-length, which
> violates RFC-2132 section 8.8 that states this option has a minimal length
> of 1.
>
> Practical consequence: dhcpcd 3.2.3 on Linux (tried openSUSE 11) sees a
> packet with malformed option (zero-length) and discards the packet and is
> unable to obtain an IP address. Leaving this option commented out, dhcpcd
> gets the IP address as desired.
>
> For reference, ISC dhcpd doesn't send option 47 in response if it is
either
> not configured at all, or if configured to be the empty string
> (with: option netbios-scope="";)
>
> I'd suggest to either adjust the configuration suggestion to be in
> compliance with RFC-2132, or, a bit stricter, make sure that this option
> isn't sent with zero length.
>
> Reference:
> bug report against dhcpcd
> <http://bugs.marples.name/show_bug.cgi?id=112>
>
> Thanks in advance & best regards
>
Thanks for the report.

I'm no expert on NetBios configuration (in fact I know almost nothing
about it....) Those suggested options came from a third party, long ago.

Is there a "empty netbios scope" which is one character long? If not,
I'm inclined simply to delete that line from the example file, or maybe
change to to show how to set the scope to "example.com" or similar.

Cheers,

Simon.

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