Grandstream Networks GXV34 0 Series Manual page 34

Specifies which NAT traversal mechanism will be enabled on the phone system. It can be selected from the
dropdown list:
NAT NO
STUN
Keep-alive
UPnP
Auto
OpenVPN®
If the outbound proxy is configured and used, it can be set to "NAT NO".
NAT Traversal
If set to "STUN" and STUN server is configured, the phone system will periodically send STUN message to
the SUTN server to get the public IP address of its NAT environment and keep the NAT port open. STUN
will not work if the NAT is symmetric type.
If set to "Keep-alive", the phone system will send the STUN packets to maintain the connection that is first
established during registration of the phone. The "Keep-alive" packets will fool the NAT device into
keeping the connection open and this allows the host server to send SIP requests directly to the registered
phone.
If it needs to use OpenVPN to connect host server, it needs to set it to "VPN". If the firewall and the SIP
device behind the firewall are both able to use UPNP, it can be set to "UPNP". The both parties will
negotiate to use which port to allow SIP through. The default setting is "Keep-alive".
Adds the Proxy-Required header in the SIP message. It is used to indicate proxy-sensitive features that
Proxy-
must be supported by the proxy. Do not configure this parameter unless this feature is supported on the
Require
SIP server.
Account/SIP/SIP Settings
SIP Basic
Settings
SIP Allows the phone system to send SIP REGISTER messages to the proxy/server.
The default setting is "Yes".
Registration
Controls whether to clear SIP user's information by sending un-register request to the proxy server.
When set to "All", the un-registration is performed by sending a REGISTER message with "Contact"
header set to * and Expires=0 parameters to the SIP server when the phone starts pre-registration after
rebooting.
Unregister
before New
If set to "Instance", the phone only cleans the current SIP user's info by sending REGISTER message with
Registration
"Contact" header set to concerned SIP user's info and Expires=0 parameters to the SIP server.
The default setting is "Instance".
Register Configures the time period (in minutes) in which the phone refreshes its registration with the specified
Expiration registrar. The default setting is 60.
(m)
The maximum value is 64800 (about 45 days).
Specifies the frequency (in minutes) in which the phone refreshes its subscription with the specified
Subscribe
registrar. The maximum value is 64800 (about 45 days).
Expiration
Default value is 60.
(m)
Re-register
Specifies the time frequency (in seconds) that the phone sends re-registration request before the Register
before
Expiration. The default setting is 0.
Expiration
The range is from 0 to 64,800.
(s)
Table 20: Account/SIP/General Settings