Internet Security and Acceleration (ISA) Server 2004 Standard Edition SP1 provides the latest updates to ISA Server 2004, with increased security, reliability and stability. Microsoft strongly encourages customers to install SP1 on all computers running ISA Server 2004 Standard Edition.
ISA Server 2004 Standard Edition SP1 can be installed directly on computers running ISA Server 2004 Standard edition, and includes:
1) All software updates issued since ISA Server was released to manufacturing.
2) Fixes for common issues reported by customers through Microsoft Product Support Services (PSS).
3) Enhanced stability of the ISA Server services and administration tool in a number of scenarios.
Download:
http://www.microsoft.com/downloads/details.aspx?FamilyID=69c5d85c-5c80-473c-9cb4-60dda75d568d&DisplayLang=en