You can select the communication protocol that Symantec Protection Engine uses to communicate with the client applications for which it provides scanning services. You must configure protocol-specific configuration options, which differ depending on the protocol that you select.
You can choose from the following protocols:
Internet Content Adaptation Protocol (ICAP)
Symantec Protection Engine uses ICAP by default. ICAP is a lightweight protocol for executing a remote procedure call on HTTP messages. Symantec Protection Engine supports version 1.0 of ICAP, as presented in RFC 3507 (April 2003).
Symantec Protection Engine includes its own Native protocol. The Native protocol is a TCP/IP based protocol. It is text-based like HTTP or SMTP. It uses ASCII commands and responses to communicate between the client and the server.