North American Network Operators Group
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Re: Open Letter to D-Link about their NTP vandalism

  • From: Valdis.Kletnieks
  • Date: Mon Apr 10 00:06:23 2006 
On Sat, 08 Apr 2006 11:17:20 CDT, Nicholas Suan said:
> It would be nice if it were that simple. However there are an annoyingly
> large amount of poorly-written clients whose polling ratios do not
> decrease after they get no response from the server. There have even
> been some clients whose polling rate *increases* after they get no
> response.

One particular piece of crapware of the tucows archive variety would retry
once per second if it hadn't heard a response - but a ICMP Port Unreachable
would trigger an *immediate* query, so it would basically re-query at whatever
the RTT for the path was.

Said software was why instead of leaving NTP disabled on the before-mentioned
box, and hoping that at least *some* people would clue in from the ICMP reply,
I had to basically firewall and drop the packets entirely.

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