Figure 6-20: Voice - Sip Screen - Pbx Parameters - Linksys SPA9000 User Manual

IP Telephony System
Insert VIA received. This lets you insert the received parameter into the VIA header of SIP responses if the
received-from IP and VIA sent-by IP values differ. Select yes or no from the drop-down menu. The default is no.
Insert VIA rport. This feature lets you insert the rport parameter into the VIA header of SIP responses if the
received-from port and VIA sent-by port numbers differ. Select yes or no from the drop-down menu. The default
is no.
Substitute VIA Addr. This feature lets you use NAT-mapped IP:port values in the VIA header. Select yes or no
from the drop-down menu. The default is no.
Send Resp To Src Port. This feature lets you send responses to the request source port instead of the VIA sent-
by port. Select yes or no from the drop-down menu. The default is no.
STUN Enable. This feature lets you use STUN to discover NAT mapping. Select yes or no from the drop-down
menu. The default is no.
STUN Test Enable. If the STUN Enable feature is enabled and a valid STUN server is available, then the System
can perform a NAT type discovery operation when it powers on. It will contact the configured STUN server, and
the result of the discovery will be reported in a Warning header in all subsequent REGISTER requests. If the
System detects symmetric NAT or a symmetric firewall, NAT mapping will be disabled.
The STUN Test Enable feature lets you use the STUN test. Select yes or no from the drop-down menu. The default
is no.
STUN Server. Enter the IP address of the STUN server to contact for NAT mapping discovery.
EXT IP. Enter the external IP address to substitute for the actual IP address of the System in all outgoing SIP
messages. If 0.0.0.0 is specified, then no IP address substitution will be performed.
EXT RTP Port Min. This is the external port mapping number of the RTP Port Min. number. If this value is not
zero, then the RTP port number in all outgoing SIP messages will be substituted for the corresponding port value
in the external RTP port range.
NAT Keep Alive Intvl. This is the interval between NAT-mapping, keep alive messages. The default is 15.
PBX Parameters
Proxy Network Interface. This tells the System how the clients (usually phones) are connected. Select LAN or
WAN. The default is WAN.
Proxy Listen Port. This is the port used by the System when it listens for client messages at the selected

Figure 6-20: Voice - SIP Screen - PBX Parameters

interface. The default is 6060.
Chapter 6: Using the Web-based Utility 39
The Voice Tab
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