In order to send web traffic transparently to the Web Security Appliance (WSA), the system administrator can use one of these two methods:

Policy-based routing (PBR) on the network infrastructure: This method allows the administrator to define routing policies based on the source or destination IP address, port number, protocol, or other criteria of the web traffic. The administrator can then apply these policies to the network interfaces or subinterfaces and redirect the matching traffic to the WSA. This method does not require any configuration on the client side and can be applied to any type of web traffic, including HTTPS and FTP. However, this method may require additional network resources and maintenance, as well as coordination with other network administrators.

Web Cache Communication Protocol (WCCP) on the WSA and the network device: This method allows the administrator to configure the WSA and the network device (such as a router, switch, or firewall) to communicate with each other using WCCP, a Cisco proprietary protocol. The network device acts as a WCCP router and redirects the web traffic to the WSA, which acts as a WCCP client. The WSA then processes the traffic and returns it to the network device, which forwards it to the original destination. This method does not require any configuration on the client side and can be applied to HTTP, HTTPS, and native FTP traffic. However, this method requires that the network device supports WCCP and that the WSA and the network device are in the same Layer 2 domain.