SIP Header Pre-Processing HMR
By default, the Oracle® Enterprise Session Border Controller (E-SBC) performs in-bound SIP manipulations after it carries out header validation. Adding the inmanip-before-validate option in the global SIP configuration allows the E-SBC to perform HMR on received requests prior to header validation. Because there are occaisional issues with other SIP implementations—causing invalid headers to be used in messages they send to the E-SBC—it can be beneficial to use HMR to remove or repair these faulty headers before the request bearing them are rejected.
When configured to do so, the E-SBC performs pre-validation header manipulation immediately after it executes the top via check. Inbound SIP manipulations are performed in order of increasing precedence: SIP interface, realm, and session agent.
The fact that the top via check happens right before the E-SBC carries out pre-validation header manipulations means that you cannot use this capability to repairs the first via header if it is indeed invalid. If pre-validation header manipulation were to take place at another time during processing, it would not be possible to use it for SIP session agents. The system learns of matching session agents after top via checking completes.
For logistical reasons, this capability does not extend to SIP responses. Inbound manipulation for responses cannot be performed any sooner that it does by default, a time already preceding any header validation.
To enable SIP header pre-processing:
