Internet Content Adaptation Protocol
Internet Content Adaptation Protocol ( ICAP ) is a protocol for the simple forwarding of content for HTTP , HTTPS and FTP -based services.
target
In general, ICAP is a lean protocol for executing a " Remote Procedure Call " for HTTP (S) and FTP. ICAP clients can forward HTTP data to an ICAP server, which in turn transforms or processes ("adapts") the content. The server sends the data back to the client after processing. Usually the adapted content is HTTP (S) / FTP requests or responses.
There are also products known that use ICAP in a modified version for mail filtering, such. B. the webwasher .
function
An ICAP client is usually a proxy that accepts HTTP (S) / FTP requests from a browser. The data is sent to an ICAP server to be processed there. This processing can be a check of the URL , a virus scan, etc. The server sends a response back, which then goes back to the browser via the ICAP client and is displayed there. By default, ICAP uses TCP port 1344.
For forwarding, the HTTP (S) / FTP data is packed in an ICAP packet and forwarded to the server. A distinction is made between two modes for forwarding. There is reqmod (request modification) for the requests and respmod (response modification) for the content . This differentiation enables content filters , for example , to save bandwidth in addition to blocking unwanted requests. Requests that are already blocked in the reqmod do not cause any further loading of Internet content, which saves bandwidth.
Web links
Individual evidence
- ↑ Jeremy Elson: Jeremy Elson and Alberto Cerpa, Editors. Retrieved May 3, 2017 .