Windows 2000 and Windows Me have a totally different networking stack than Windows 95, 98 and 98 SE. Windows 2000 and Me do not need DUN 1.4.
Navigating archive.org is slow. Successful searches are never guaranteed. Usually, I first search for an old URL using Google and then directly enter the old URL into archive.org's Wayback Machine. In this case, I used Google to figure out that, in 2002, Microsoft's Italian homepage was microsoft.com/italy. I could access microsoft.com/italy through archive.org. From the Italian homepage, I navigated to the Windows product page, then the Windows 98 page, then the Windows 98 Downloads page, then the DUN 1.4 information page and finally the DUN 1.4 download page. The script on that page doesn't work anymore, so I had to View Source to get the URLs for the Italian DUN 1.4 files. Luckily, archive.org has those Italian DUN 1.4 file URLs, even though navigating to them through the archived Microsoft webpages was impossible.