Yeastar Technology MyPBX U200, Руководство администратора

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MyPBX U200 Administrator's Guide
www.yeastar.com Page 96
Figure 6-57
2) NAT
Note : Configuration of this section is only required when using remote
extensions.
· Enable STUN
STUN (Simple Traversal of UDP through NATs) is a protocol for assisting devices
behind a NAT firewall or router with their packet routing.
· STUN Address
The STUN server allows clients to find out their public address, the type of NAT
they are behind and the internet side port associated by the NAT with a
particular local port. This information is used to set up UDP communication
between the client and the VOIP provider and so establish a call.
· External IP Address
The IP address that will be associated with outbound SIP messages if the system
is in a NAT environment.
· External Host
Alternatively you can specify an external host, and the system will perform DNS
queries periodically.
This setting is only required when your public IP address is not static. It is
recommended that a static public IP address be used with this system. Please
contact your ISP for more information.
· External Refresh Interval
If an external host has been supplied, you may specify how often the system will
perform a DNS query on this host. This value is specified in seconds.