# Define SIP Protocol parameters

The Session Initiation Protocol (SIP) agent can be used to handle multimedia connections that use SIP as their transfer protocol.

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Using the agent allows SIP to be used across a firewall that uses NAT. SIP uses TCP or UDP port 5060 to initiate the connection, after which the traffic is allocated a dynamically assigned port. The Protocol Agent monitors the actual ports used, so that the range of dynamic ports does not need to be allowed in the firewall policy.

The SIP agent can be configured to force the client or server address used within the SIP transport layer to be used also for the media stream carried over SIP. This configuration is by default set for both client and server.
Note: Connections used for file transfer and whiteboard drawing are not allowed by the SIP Protocol Agent. Allow them in a different rule as necessary.

For more details about the product and how to configure features, click Help or press F1.

## Steps

1. In the properties of a custom Service you have created, click Select next to the Protocol field and select SIP.
2. On the Protocol Parameters tab, set the parameters for the Protocol.
3. Click OK.