[ntp:questions] server's address in ntp payload?
Danny Mayer
mayer at gis.net
Fri Nov 18 14:24:34 UTC 2005
Ulisses wrote:
> Hello Danny
>
> On Thu, Nov 17, 2005 at 09:29:17PM -0500, Danny Mayer wrote:
>
>>Ulisses wrote:
>>
>>>Hello all
>
> [...]
>
>>No you are not wrong, but why would you want to?
>
>
> The usefulness I wanted with it is to try getting the
> loopback address of ntp servers running on routers
>
That's confusing me. Do you really mean the loopback addresss -
127.0.0.1 and ::1 or did you mean an address bound to the interface?
> (for good purposes)
>
> Also It would be useful if I could extract from ntp, any
> Globally Unique Identifier I could get from NTP protocol that
> could identify the same ntpd process in a multi-homed router.
>
There nearest thing to an identifier is the refid. Unfortunately it's
flawed in the NTP reference implmentation since you can get different
refid's from different addresses on the machine.
> The only reliable way to achieve it I have figured out is
> (more or less) to extract the ntp stats and compare them when
> possible
>
>
>>Are you asking about the server sending the packet?
>
>
> Host A Host B (Router)
>
> query
> ntpdc/ntpq/ntpd --------------> ntpd
> <-------------
> reply
>
> I want to know from Host A, the address of Host B looking an ntp header
>
I don't understand. Are you asking that, sitting at Host A, you send a
packet to host B and then you get in the response the address that Host
B sees as receiving the request from?
The answer is that it's the address of the interface receiving the
packet. There was a bug, long since fixed, which resulted in a packet
being returned to a different address.
Danny
More information about the questions
mailing list