Permanent link to NET framework 3.5

The setup installer, automatically try to donwload the Net Framework 3.5, but I wish to give the user a link to the full package in the download Microsoft site.

The problem is that Microsoft frequently changes URLs. ¿Somebody know a way to proportionate a permanent link?

When Microsoft change their URLs, they usually notify you that the URL has changed, and automatically redirect you to the new URL.