The following is a list of issues to consider before and after you begin the upgrade process:
- Log files will be deleted during the upgrade process. ISA Server 2004 log files are not compatible with ISA Server 2006. If you need an archive copy of your log files, see Back Up ISA Server 2004 Log and Cache Files.
- Cache files will be deleted during the upgrade process. To back up your cache files, see Back Up ISA Server 2004 Log and Cache Files.
- ISA Server 2004 SP2 HTTP compression settings are not properly upgraded. Record your HTTP compression settings and reconfigure HTTP compression settings after the upgrade to ISA Server 2006 is complete.
- DiffServ settings are not upgraded to ISA Server 2006. Record your DiffServ settings and reconfigure DiffServ settings after the upgrade to ISA Server 2006 is complete.
When upgrading from ISA Server 2004 Standard Edition, the following change to authentication security is implemented:
- When you use HTTP-to-HTTP bridging, ISA Server will not allow traffic on the external HTTP port when the Web listener is configured to request Basic, forms-based, or Remote Authentication Dial-In User Service (RADIUS) authentication. This is a security-related change. These credentials should be encrypted, and not sent in plaintext over HTTP.
- The ISA Server 2004 Microsoft Management Console (MMC) snap-in can be upgraded to ISA Server 2006 MMC. The ISA Server 2004 and ISA Server 2006 MMC cannot reside on the same computer.
- Firewall logging and Web proxy logging for Microsoft SQL Server™ database settings are not upgraded. Log settings revert to the Microsoft SQL Server Desktop Engine (MSDE) database. Record your SQL Server database settings and reconfigure your Firewall and Web proxy log settings after the upgrade to ISA Server 2006 is complete.
For more information on upgrading ISA 2004 firewalls to ISA 2006, check out Microsoft’s official upgrade guide at: http://www.microsoft.com/technet/prodtechnol/isa/2006/upgrade_guide_se.mspx
Thomas W Shinder, M.D.
MVP — ISA Firewalls