If you have an old Knowledgebase article, and the domain name says info.apple.com with something around it, that link is no longer valid. To find a corresponding valid link, take the end number of the article, and plug it into the 'x' in this link,
and copy/paste it into http://www.archive.org/ For instance, when you copy/paste http://docs.info.apple.com/article.html?artnum=307069 you'll get
http://support.apple.com/kb/HT1642 clicking on the December 2011 version of the history of the link.
Generally mid to late 2011 archived versions of the link will redirect you to the correct knowledgebase article that exists today. If you find a link that no longer has any historical reference, and need it, please by all means submit feedback to the webmaster:
In the case where you have an old link with an n before the article number, copy the number in place of the 'x' in the link above. All three of these links point to references that come from the old article 302758, which would then be needed to be searched under
http://docs.info.apple.com/ link shown below:
You take the right hand link and then put it in Archive.org for your search.
Downloading older software updates from these links is documented here: