ICAP servers are frequently deployed on the edge near Traffic Server proxies, adding minimal latency on file transmission.
By performing virus scanner on a remote server, local resources are not used, allowing the main thread on the server be more performant. Performing virus scanning via ICAP has several advantages over the traditional local host virus scanner deployment model. Therefore, ICAP has become an industry standard for Anti Virus service. It is very handy to request transformations on HTTP requests and responses since ICAP servers are set up on the edge of the Internet. ICAP is a light-weight protocol for executing a remote procedure call on HTTP messages. Parameter debug_enable will enable debug mode, which, in cases of ICAP server connection error or ICAP server too busy to handle the request, will return the origin response body to the client instead of an error message.
There are 4 parameters to this plugin: the scanner_server_ip and scanner_server_port (standard ICAP port is 1344) is required to initiate connection to the ICAP server, and the avoid_port is specified to avoid processing traffic that appears on particular ports (e.g, requests passed via the parent select and already checked). Icap_plugin.so scanner_server_ip scanner_server_port avoid_port debug_enable
