ISO files (disc images) were the standard method for installing the server. Windows Server 2003 | Specs, reviews and EoL info - InvGate

This article will explore what Exchange Server 2003 was, why the .iso file remains a sought-after item, the legal and security implications of finding it, and—most importantly—how to safely migrate away from it.

Exchange 2003 was one of the first major server applications to deeply integrate with the Windows Server 2003 Volume Shadow Copy Service. This allowed for snapshot backups of the database while it was online and being written to. For system administrators restoring the system state, the ability to mount an ISO, run setup /disasterrecovery , and reinstate the server configuration became the gold standard for recovery procedures for the next decade.