Port allocations for NAT traversal 

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The Sametime® Connect client will dynamically allocate UDP ports as a result of ICE negotiation.

Ephemeral ports are allocated on clients and are assigned by the client's operating system. Ephemeral ports are usually in the range of 1024-5000 and are dynamically re-allocated by the operating system as needed. Proper function of the Sametime NAT traversal feature requires open access to UDP ports on both the TURN server and the Media Manager's Packet Switcher.

Note: UDP is the preferred protocol; TCP should be used only if UDP is not available (for example, due to company policy).

For more information on ports used by a Sametime deployment, see Ports used by Sametime servers.

The following table lists the ports used for NAT traversal on the Sametime TURN Server:

Table 1. Sametime TURN Server ports opened for NAT traversal

Default port	Used for
3478	UDP or TCP, for basic STUN/TURN protocol handling. This port should be reachable by internal and external clients and by the Packet Switcher.
49152 - 65535	UDP, for dynamically allocated packet relay.

The following table lists the ports opened between the Media Manager's Packet Switcher component (which functions as the MCU) and Sametime clients residing on the corporate intranet:

Table 2. Packet Switcher ports opened for internal clients

Default port	Used for
42000 - 43000	UDP, for audio when the Packet Switcher is operating in multiple ports mode (the default mode).
46000 – 47000	UDP, for video when the Packet Switcher is operating in multiple ports mode (the default mode).

It is strongly recommended that you use the default values for these ports. These port numbers must not be subject to third-party load balancing, packet rewriting (NAT/PAT), or other network-layer manipulation.

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