* July 2004 TurnTide Acquisition
* June 2004 Brightmail Acquisition
* February 2004 ON Technology Corp. Acquisition
* December 2003 PowerQuest Corporation Acquisition
* October 2003 Safeweb, Inc. Acquisition
* August 2002 Riptech, Inc. Acquisition
Recourse Technologies Acquisition
SecurityFocus Acquisition
* July 2002 Mountain Wave Acquisition
* October 2001 Lindner & Pelc Acquisition
* July 2001 Foster-Melliar Acquisition
* December 2000 AXENT Technologies Acquisition
* February 2000 L-3 Network Security Acquisition
* December 1999 ACT! and Visual Café Divestiture
* July 1999 URLabs Acquisition
* November 1998 Quarterdeck Corporation Acquisition
* September 1998 Acquisition of Intel's antivirus business and systems management technology
* June 1998 Binary Research Limited (Ghost) Acquisition
* May 1998 Acquisition of IBM's antivirus business and immune system technology
* November 1995 Delrina (WinFax) Acquisition
* June 1994 Central Point Software Acquisition
* August 1990 Peter Norton Computing, Inc. Acquisition