At 09:27 AM 12/3/99 +0100, Harald Tveit Alvestrand wrote:
>At 11:43 01.12.99 -0500, Christian Huitema wrote:
>>At 10:49 PM 11/30/99 -0500, Keith Moore wrote:
>>
>> >note also that DNS is often slow, and seems less reliable than IP.
>> >by increasing the reliance on DNS you increase the probability of failure.
>>
>>Data point: out of 40,000 random DNS requests logged on my work station
>>over the last year, 20% underwent at least one retransmission, resulting in
>>service times larger than 2 seconds. The average packet loss rate on the
>>regular IP service only explain about half of these retransmissions, which
>>makes me suspect that a lot of additional losses are caused by congested
>>DNS servers. Increasing our reliance on the DNS is definitely not a good
idea.
>
>(Wow - a real measurement! Can this be the IETF list....? Thanks!)
>
>Question: Out of those 8.000 retransmitted DNS queries, do you have any
>data on how many eventually returned data, versus how many resulted in
>NXDOMAIN or no data?
>There used to be a bug with caching of negative responses....
All the 40,000 requests that I mentioned were eventually successfull. At
the same time, there were an additional set of requests, about 2,000, that
were not successful. The reasons for not succeeding vary from
misconfiguration to bad input, e.g. trying obsolete URLs. The unsuccessful
queries are not considered in the statistics.
-- Christian Huitema
