Specifications

Mediatrix 4100 155
C HAPTER
13
STUN Configuration
This chapter describes how to configure the STUN client of the Mediatrix 4100.
What is STUN?
STUN (Simple Traversal of UDP through NATs) is a simple client / server protocol that uses UDP packets to
discover the configuration information of NATs and firewalls between a device and the public Internet:
 NAT type
 NAT binding public address
 NAT binding time to live
NAT (Network Address Translator) is a device that translates the IP address used within a “private” network
to a different IP address known in another “public” network. See “NAT Traversal” on page 267
for more
details.
STUN supports a variety of existing NAT devices and does not require any additional hardware or software
upgrades on the NAT device.
The Mediatrix 4100 uses the STUN protocol to discover its NAT binding for the following two IP addresses/
ports (sockets):
 RTP IP address/port
 T.38 IP address/port
Restrictions on the Media5 STUN Implementation
 The Mediatrix 4100 does not currently support NAT type discovery.
 The Mediatrix 4100 does not currently support STUN NAT binding time to live discovery.
 The Mediatrix 4100 does not currently support the TLS security mechanism.
 Due to a limitation of most routers, an RTP portal might be required in order for two units behind
the same NAT/firewall to be able to communicate with each other.
Standards Supported RFC 3489 – STUN - Simple Traversal of User Datagram Protocol (UDP)
Through Network Address Translators (NATs)