In most cases, the available network bandwidth and especially that of the Internet link can be secured by ISA Server running on available entry-level hardware. A typical default deployment of ISA Server securing outbound Web access for Hypertext Transfer Protocol (HTTP) traffic requires specific hardware configurations for various Internet links. These hardware configurations are shown in the following table. (For details, see Web Proxy Scenarios in this document.).
Internet link bandwidth Up to 5 T1 7.5 megabits per second (Mbps) Up to 25 Mbps Up to T3 45 Mbps Up to 90 Mbps Processors/Cores
1
1
2
2/2
Processor type
Pentium III750 megahertz(MHz) or higher
Pentium 4 3.0–4.0 gigahertz(GHz)
Xeon3.0–4.0 GHz
Xeon Dual Core
AMD Dual Core
2.0–3.0 GHz
Memory
512 megabytes(MB)
512 MB
1 gigabyte (GB)
2 GB
Disk space
150 MB
2.5 GB
5 GB
10 GB
Network adapters
10/100 Mbps
10/100 Mbps
100/1000 Mbps
100/1000 Mbps
Concurrent virtual private network (VPN) remoteaccess connections
150
700
850
2000
Using transport layer stateful filtering instead of Web Proxy Filter improves CPU utilization for the same traffic patterns by a factor of 10. Both stateful filtering and application filtering can be used in parallel to provide granular control over performance.