Short answer: No.
There is typically a 10 concurrent connection limitation on Windows Web Server 2008, which would limit throughput substantially. Further, we don’t recommend using anything but Windows 2008 R2 SP1 with .NET 3.51 enabled.
This from the planning and implementation guide:
Recommended Internet gateway hardware
Symantec recommends having at least two Internet gateways to provide failover options, load balancing, and to maintain communication continuity. Each Internet gateway can serve multiple Notification Servers. This configuration is supported even if Notification Servers are organized in a hierarchy structure. Each Internet gateway supports 1- 60,000 endpoints and 3,000 concurrent connections.
See “About Cloud-enabled Management” on page 29.
Running Internet gateway on a virtual computer is not recommended. Running
Internet gateway on virtual hardware can lower its scalability by up to 40%.
Table 4-6
Hardware recommendations for Internet gateway
Operating System Requirement: Windows 2008 R2 SP1 with .NET Framework 3.5.1 feature enabled
Processor Recommendation: Dual-core CPU
Drive Space Recommendation: At least 40 GB
RAM Recommendation: 8 GB
Network Recommendation: Two 1Gbit network adapters