Andreas Plesner Jacobsen wrote:
I've recently been introduced to the caching behaviour of InetAddress,
and I think it may be improved.
The javadoc reads:
The InetAddress class has a cache to store successful as well as
unsuccessful host name resolutions. The positive caching is there to
guard against DNS spoofing attacks; while the negative caching is used
to improve performance.
And that is all fine and well, but for multihomed hosts, I believe the
current behaviour is
1) Not documented properly
2) Not correct
Coming from a unix-world, I'm used to the resolver handing out
RR-replies in random order, and thus I would expect InetAddress to do
the same,
The specification could be improved but changing InetAddress.getByName
to return a random address is a significant change that could break
existing applications. It might be better to define a new method,
perhaps "getAnyByName", that randomly chooses one of the cached
addresses for the host (or does a lookup if not in the cache). That
would be a convenience to applications to avoid needing to invoke
getAllByName and choose an address themselves.
-Alan.
