Topology Hiding for IWF with an Internal Home-Realm

You can configure the SBC to mask the IP address of the originating caller in the SIP From and/or P-Asserted-Identity headers when calls are placed from H.323 to SIP endpoints.

The option NoPAssertedID checks for incoming SETUP messages have the presentation indicator set to restricted and instructs the SBC to send a Privacy header without the P-Asserted-Identity and not to make the From header anonymous.

The option replace-call-origin-ip removes the calling party’s IP address in the SIP From header. The IP address from the internal home realm is used instead.

The topology hiding feature uses the presentation indicator field from an inbound H.323 setup message to determine if/how the headers will be masked. The following table summarizes the configurable SBC parameters and the values for the From and P-asserted-identity headers.

H.255 Presentation Indicator Setting	P-Asserted-Identity Header Value	From Header Value	SD Session Agent Option
Allow	IP address from home realm of SD SIP Config	H.255 Calling Party IP/Port	No Option Set
Allow	IP address from home realm of SD SIP Config	IP address of Home Realm SIP-Interface	NoPAssertedID
Allow	IP address from home realm of SD SIP Config	IP address of Home Realm SIP-Interface	replace-call-origin-ip
Allow	IP address from home realm of SD SIP Config	IP address of Home Realm SIP-Interface	replace-call-origin-ip, NoPAssertedID
Restricted	PAI Header not present	Anonymous	No Option Set
Restricted	PAI Header not present	Anonymous	NoPAssertedID
Restricted	PAI Header not present	Anonymous	replace-call-origin-ip
Restricted	PAI Header not present	Anonymous	NoPAssertedID, replace-call-origin-ip

IWF Topology Hiding Configuration

To enable IWF topology hiding on your Oracle Communications Session Border Controller :

In Superuser mode, type configure terminal and press Enter.
```
ORACLE# configure terminal
```
Type session-router and press Enter to access the signaling-level configuration elements.
```
ORACLE(configure)# session-router
ORACLE(session-router)#
```

Type sip-config and press Enter. The system prompt changes.

ORACLE(session-router)# session-agent	
ORACLE(session-agent)#

Use the ACLI select command so that you can work with the session agent configuration to which you want to add these options.
```
ORACLE(session-agent)# select
```
options—Set the options parameter by typing options, a Space, the option name preceded by a plus sign (+) (replace-call-origin-ip), and then press Enter. Follow the same steps to add the NoPAssertedID option.
```
ORACLE(session-agent)# options +replace-call-origin-ip
ORACLE(session-agent)# options +NoPAssertedID
```
If you type either of these options without the plus (+) sign, you will remove any previously configured options. In order to append the new option to the options list, you must prepend the new option with a plus sign as shown in the example above.