Figure 2. The IIS 5.0 Architecture. IIS 5.0 provides three application modes: In-Process, Pooled Out-of-Process, and Isolated Out-of-Process. The latter is the most secure mode but is seldom used because it requires more resources than the other two modes. The disadvantage of the other two modes is that they share resources with other applications. This means that if someone can manage to corrupt one application, he or she might be able to corrupt the entire process.