iRules commands and events enables the usage of ICAP (Internet Content Adaptation Protocol) servers to modify HTTP requests and responses. . The ICAP* events can take any ICAP, SSL, TCP, or IP commands, except:
  • The ICAP::header command can only be used in ICAP* events.
  • The ICAP::method and ICAP::uri commands can only be used in ICAP_REQUEST events.
  • The ICAP::status command can only be used in ICAP_RESPONSE events.
  • The ICAP feature requires either an LTM or PEM license (ADAPT is not restricted).



  • ICAP_REQUEST - raised after an ICAP command has been created but before it has been sent to an ICAP server
  • ICAP_RESPONSE - raised after an ICAP response has been processed but before the result is sent back to the HTTP adaptation virtual server