AudioCodes Mediant 4000 SBC User Manual page 919

CHAPTER 60 Configuration Parameters Reference
Parameter
NAT Parameters
'NAT Traversal'
configure voip >
media settings >
disable-NAT-traversal
[NATMode]
■ [1] = Enable. The device forwards received STUN
packets.
Note: The parameter is applicable only to the SBC
application.
Enables the NAT traversal feature for media when the device
communicates with UAs located behind NAT.
■ [0] Enable NAT Only if Necessary = NAT traversal is
performed only if the UA is located behind NAT:
✔
UA behind NAT: The device sends the media
packets to the IP address:port obtained from the
source address of the first media packet received
from the UA.
✔
UA not behind NAT: The device sends the packets to
the IP address:port specified in the SDP 'c=' line
(Connection) of the first received SIP message.
Note: If the SIP session is established (ACK) and the
device (not the UA) sends the first packet, it sends it to
the address obtained from the SIP message and only
after the device receives the first packet from the UA
does it determine whether the UA is behind NAT.
■ [1] Disable NAT = (Default) The device considers the UA
as not located behind NAT and sends media packets to
the UA using the IP address:port specified in the SDP
'c=' line (Connection) of the first received SIP message.
■ [2] Force NAT = The device always considers the UA as
behind NAT and sends the media packets to the IP
address:port obtained from the source address of the first
media packet received from the UA. The device only
sends packets to the UA after it receives the first packet
from the UA (to obtain the IP address).
■ [3] NAT by Signaling = The device identifies whether or
not the UA is located behind NAT based on SIP signaling.
The device assumes that if signaling is behind NAT that
the media is also behind NAT, and vice versa.
✔
UA behind NAT: The device sends media according
to option Force NAT (2). If the 'Media Latch Mode'
parameter is configured to Strict, the 'Media Latch
Mode' parameter automatically changes to Dynamic.
✔
UA not behind NAT: The device sends media
according to option Disable NAT (1).
■ [4] NAT by Signaling Restricted IP = The device
identifies whether or not the UA is located behind NAT
based on SIP signaling. The device assumes that if
signaling is behind NAT that the media is also behind
NAT, and vice versa.
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Mediant 4000 SBC | User's Manual
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