[ntp:questions] Re: Different types of associations in the ntpq billboard

Danny Mayer mayer at ntp.isc.org
Tue Apr 11 16:14:58 UTC 2006

Heiko Gerstung wrote:
> Danny Mayer wrote:
>> Ronan Flood wrote:
>>> mayer at ntp.isc.org (Danny Mayer) wrote:
>>>>> Looking at ntpq_ops.c/decodeaddrtype(), it only shows "b" for an IPv4
>>>>> non-multicast destination address ending in 255 -- I guess you're
>>>>> subnetting, or using IPv6.
>>>> That's not surprising since that basically defines broadcasting. IPv6
>>>> does not have broadcast.
>>> Fair enough for IPv6 then, but in IPv4 if your local net is say
>>>, your broadcast address is
>>> Perhaps some use should be made of pmode=MODE_BROADCAST?
>> Probably, but ntpq receives the data as-is and doesn't have access to
>> that information. I will have to take another look at the definition of
>> broadcast before I respond to the first part of your question.
> The information that this is a broadcast packet should be in the ntp
> packet itself, no? (mode 5 = broadcast)

How would you know? ntpq uses a mode 6 packet. You actually need to look
at the data stored in the association.


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