One of the design requirements
of Amazon S3 is extremely high availability. One of the ways we meet this
requirement is by updating the IP addresses associated with the Amazon S3
endpoint in DNS as needed. These changes are automatically reflected in
short-lived clients, but not in some long-lived clients. Long-lived
clients will need to take special action to re-resolve the Amazon S3
endpoint periodically to benefit from these changes. For more information
about virtual machines (VMs). refer to the following:
For Java, Sun's JVM caches DNS lookups forever by
default; go to the "InetAddress Caching" section of the
InetAddress documentation for information on how to change this behavior.
For PHP, the persistent PHP VM that runs in the
most popular deployment configurations caches DNS lookups until
the VM is restarted. Go to the
getHostByName PHP docs.