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Web-based bug reporting system for Linux without database server
BugBye
Web-based bug tracking system in ASP.NET and C#
BugHost
Hosted bug and defect tracking service
Bugs Online
ASP and Access bug tracking system for IIS
BUGtrack
Hosted bug tracking, issue tracking and project management
BugTracker.NET
Web-based bug tracker in ASP.NET, C# and SQL Server