[dns-operations] Behavior of browsers with absolute HTML links (Was: compressing DNS traffic data
Ed.Lewis at neustar.biz
Tue Dec 14 15:02:13 UTC 2010
At 11:52 -0200 12/13/10, Carlos Martinez-Cagnazzo wrote:
>> What is the behaviour of a Web browser when there are several
>> *asbolute* links with the same "prefix"? I would have assume that two
>> links <http://www.example.org/foo.html> and
>> <http://www.example.org/bar.html> create only one DNS request?
>That would certainly be the expected behaviour. Otherwise, they are
>doing something wrong.
Funny how things go 'round and 'round. Not too many years ago we
wished applications, and specifically web browsers, wouldn't use
their own caches. Back then, applications would do a look up and
then use that information for the life of the process. The problem
was that the process lifetime sometimes exceeded the TTL of the
If an application does cache DNS data, the behavior should be the
same as a DNS server/cache. That is, honor the TTL.
To answer the originator's question, if the TTL on www.example.org A
(or AAAA) is 3600 and you click on one link at 9am and the other at
10:05am, there should be two DNS requests. If the clicks were 9am
and 9:05am, then I would excuse a second stub resolver-like request
to a cache which should hit on the previous click.
OTOH, it's never a crime to ask the same question again and again.
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