Using a Randomly Generated Called User Part to Hide Original

By default, the device uses the called-party user part from the incoming SIP INVITE request for the Dynamic Push Notification Service (PNS). If you want to prevent this user part from being exposed to the Push Notification Service, you can configure the device to generate a random user part and use it instead of the original.

When the device receives an incoming INVITE request for a PNS user, it performs the following:

1.

Generates a unique random user part.

2.

Creates a temporary registration record for the random user part.

3.

Stores the random and original user parts as session variables for use in Message Manipulation rules:

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var.session.origuser - original user part

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var.session.randomuser - generated user part

4.

Sends the random user part instead of the original to the Push Notification Service.

5.

Waits for a SIP REGISTER request with the random user part from the PNS user.

6.

Matches the REGISTER request to the temporary registration record.

7.

Routes the call to the PNS user.

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To configure the use of a random user part for Dynamic PNS:

1.

Configure the 'Dynamic PNS Registration Mode' parameter to Use Random Username in the IP Group of the Push Notification Service. For more information on IP Groups, see Configuring IP Groups.

2.

Configure a Call Setup Rule that references the var.session.randomuser variable. For more information on Call Setup Rules, see Configuring Call Setup Rules.

3.

Configure Message Manipulation rules for when to use the original user part or random user part:

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Outbound leg (toward called PNS user):

When the device receives an INVITE request, the device uses a Message Manipulation rule to replace the original user part in the To and Request-URI headers with the random user part (obtained from var.session.randomuser), before sending the request to the PNS user.

When the device receives a SIP response for a non-REGISTER request, the device uses a Message Manipulation rule to replace the original user part in the From header with the random user part (obtained from var.session.randomuser), before sending the response to the PNS user.

Assign the Message Manipulation Set of these rules to the IP Group, using the 'Outbound Message Manipulation Set' parameter.

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Inbound leg (toward calling party):

When the PNS user responds to the INVITE request, the device uses a Message Manipulation rule to replace the random user part in the To and Contact headers with the original user part (obtained from var.session.origuser), before sending the response to the calling party.

When the PNS user sends a non-REGISTER request (e.g., re-INVITE), the device uses a Message Manipulation rule to replace the random user part in the From and Contact headers with the original user part (obtained from var.session.origuser), before sending the response to the calling party.

Assign the Message Manipulation Set of these rules to the IP Group, using the 'Inbound Message Manipulation Set' parameter.

For more information on Message Manipulation, see Configuring SIP Message Manipulation.