[ntp:questions] What exactly does "Maximum Distance Exceded" mean?

Joe Gwinn joegwinn at comcast.net
Mon Mar 16 13:52:49 UTC 2009

Status code values fixed.

At 10:47 PM -0400 3/15/09, Danny Mayer wrote:
>Joseph Gwinn wrote:
>>  Hmm.  OK, but I think that we've kind of run off the rails.  Let me
>>  summarize: 
>>  1.  Sun Microsystems' current behavior is not the issue, as I'm loading
>>  old software from an old CD onto old computer hardware, hardware that
>>  cannot support a newer version of Solaris than v9. 
>>  One of these old Solaris boxes did work with NTPv3 running an even older
>  > version of Solaris, with no 9514 codes, deepening the mystery.
>  >
>The trouble here is that those codes are *very likely* likely to have
>changed between V3 and V4 since there was a large rewrite between the
>two. That's why looking at the source code is necessary to get you the
>help you need.

As discussed in my other reply, mutating codes is a blunder.   It's a 
good news bad news thing.  The good news is that NTP has succeeded on 
an unimagined scale.  The bad news is that because of that scale, one 
must be *very* respectful of NTP's existing base, and it can be 

>  > The fact that this obsolete system can most likely support NTPv4 is
>>  worth investigation, though.
>>  2.  I think that what's happening is that I'm doing something dumb, and
>>  I bet that there is no real difference in how NTPv3 or NTPv4 would react
>>  to this faux pas, whatever it turns out to be.  Nor is source code
>>  research needed or requested. 
>>  3.  The original question was how to interpret a specific status code,
>>  9514.  I read the explanation in the documentation, but became no wiser
>>  for it.  Thus my question. 
>Which is why you need to look at the source code. Documentation isn't
>always clear or definitive but the source code will tell you.

It simply cannot be required to read source code to get the 
definitions of status codes, even if the documentation has to give 
one definition per NTP version.  NTP is used on hundreds of millions 
of computers.  Are we expecting that every time someone gets an 
unexpected code they either have to read the source code, or pay 
someone to read it for them?  I'm sorry, but that cannot work.

>  > If there isn't a NTP FAQ entry on this, there probably should be.  Our
>  > sysadmins were flummoxed by the cloud of 9514 codes, and they are far
>  > too busy to undertake a research project.  (The deeper problem is that
>>  some managers believe that NTP is plug and play, which isn't quite true.)
>Mostly it is, but there are always mysteries like this.



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