Jens Frank wrote:
The idea of having a dedicated http server for updates
relies on DNS
entries with a very short time to live (TTL). Else DNS servers all
over the world would cache the DNS entry for
updates.wikipedia.org
for a long time. Most DNS servers handle entries with a short TTL
correctly, but several browsers don't. They cache IP adresses, but
don't honor the TTL. Mozilla is one of those. My home box has a
dyndns.org hostname and Mozilla caches the IP for several days
despite the TTL being 5 minutes or so.
A way to overcome this problem is to append a random fourth level domain
name to the URLs pointing to the update server. This way, each time the
update server is referenced, the ip address is refreshed.
eg
Where <anything> is replaced by a random string:
http://<anything>.update.wikipedia.org/ resolves via a wildcard DNS
entry to the current ip address of
update.wikipedia.org. This way,
whenever an update link is pressed, the most up to date IP address is
fetched from the DNS.