Cisco 7821 Administration Manual page 153

Procedure
Step 1 Select Device > Device Settings > SIP Profile
Step 2 Choose the search criteria to use and click Find.
Step 3 Select the profile to modify.
Step 4
Set the Start Media Port and Stop Media Port to contain the start and end of the port range.
The following list identifies the UDP ports that are used for other phone services and thus not available for
RTP and sRTP use:
port 4051
used for the Peer Firmware Sharing (PFS) feature
port 5060
used for SIP over UDP transport
port range 49152 to 53247
used for local ephemeral ports
port range 53248 to 65535
used for the VxC single tunnel VPN feature
Step 5 Click Save.
Step 6 Click Apply Config.
Cisco IP Phone 7821, 7841, and 7861 Administration Guide for Cisco Unified Communications Manager 10.0 (SIP)
Set Up RTP/sRTP Port Range
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