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

[Matthias Andree]

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

-- 
Matthias Andree