D-Link DSL-G2452GR User Manual page 86

Section 4 - Configuration
Misc
Use default
Toggle this to use the default gateway or enter one manually.
gateway
Bound interface If Use default gateway is disabled, use the drop-down list to select
name
an interface (the local interface or an IPv4 WAN connection) which
will be used for VoIP.
Enable DHCP Move the switch to the right to allow DHCP option 120. When this
option 120 option is enabled, the Address field in the SIP Proxy section and the
Backup SIP proxy address field in the SIP Backup section will be
filled in automatically.
Local RTP port A range of ports for voice traffic receipt/transfer via RTP. Unless
(min. and max.) another setting is given by your ISP, it is recommended to leave the
default value (9000 and 9007)
SIP Domain
Use domain to Toggle the switch if your ISP requires you to specify a domain name upon
register
registration on the SIP proxy server.
SIP domain name
When this field is filled in, the router registers on the SIP proxy server
using the specified domain name. When the field is blank, the router
uses the IP address assigned to it.
D-Link DSL-G2452GR User Manual 82