For educational or legacy testing, community-maintained archives like Internet Archive host ISO images of the original 2001 release for Windows 95, 98, 2000, and NT.
Since official channels make it difficult, many users turn to third-party websites. You may find the software hosted on archive sites, university FTP servers, or developer forums.
Downloading Oracle Client version 8.1.7 (Oracle 8i) is difficult because it reached its end-of-life years ago and is no longer hosted on official Oracle download pages Why You Might Be Seeing This
