3. Information System Security Policy (ISSP)

The PSSI defines all the filtering rules to be configured on the firewall. This involves specifying all TCP/IP services and protocols that can be accessed by users inside or outside the site to be protected. It can also cover content (if the filtering mechanism so permits). The security policy depends of course on the company's security needs, which have been identified in advance, but also on the firewall's ability to meet these needs, both in terms of performance and filtering.