Yealink T21PE2 - Network Address Translation (NAT); NAT Traversal Configuration

Phone Network
45
Web UI Network->Advanced->Local RTP Port->Max RTP Port (1024~65535)
Parameter
features.rtp_symmetric.enable
[1]
<y0000000000xx>.cfg
Description
It configures the symmetrical RTP (Real-Time Transport Protocol) feature on the IP phone.
Note: IP address and port can be negotiated through the SDP protocol.
Permitted
Values
0-Disabled
1-reject RTP packets arriving from a non-negotiated IP address
2-reject RTP packets arriving from a non-negotiated port
3-reject RTP packets arriving from a non-negotiated IP address or a non-negotiated port
Default 0
[1]
If you change this parameter, the IP phone will reboot to make the change take effect.
Network Address Translation (NAT)
Network Address Translation (NAT) is a function that allows multiple devices to share the same public, routable IP
address to establish connections over the Internet. NAT is present in many broadband access devices to translate pub-
lic and private IP address.
Yealink IP phones can work with certain types of NAT.
Topics
NAT Traversal Configuration
Keep Alive Configuration
Rport Configuration
SIP Port and TLS Port Configuration
NAT Traversal Configuration
In the VoIP environment, NAT breaks end-to-end connectivity. NAT traversal is a general term for techniques that estab-
lish and maintain IP connections traversing NAT gateways, typically required for client-to-client networking applic-
ations, especially for VoIP deployments.
Yealink IP phones support three NAT traversal techniques: manual NAT, STUN and ICE. If you enable manual NAT and
STUN, the IP phone will use the manually-configured external IP address for NAT traversal. The TURN protocol is used
as part of the ICE approach to NAT traversal.
The following table lists the parameters you can use to configure NAT traversal.
Parameter
account.X.nat.nat_traversal
[1]
<MAC>.cfg
Description
It enables or disables the NAT traversal.
Note: If it is set to 1 (STUN), it works only if “static.sip.nat_stun.enable” is set to 1 (Enabled); if it is set to 2
(Manual NAT), it works only if “static.network.static_nat.enable” is set to 1 (Enabled).
Permitted
Values
0-Disabled
1-STUN
2-Manual NAT
Default 0