TD-W8980 N600 Wireless Dual Band Gigabit ADSL2+ Modem Router User Guide
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• PPTP Passthrough: Point-to-Point Tunneling Protocol (PPTP) allows the Point-to-Point
Protocol (PPP) to be tunneled through an IP network. To allow PPTP tunnels to pass
through the modem router, click Enable.
• L2TP Passthrough: Layer Two Tunneling Protocol (L2TP) is the method used to
enable Point-to-Point sessions via the Internet on the Layer Two level. To allow L2TP
tunnels to pass through the modem router, click Enable.
• IPSec Passthrough: Internet Protocol security (IPSec) is a suite of protocols for
ensuring private, secure communications over Internet Protocol (IP) networks, through
the use of cryptographic security services. To allow IPSec tunnels to pass through the
modem router, click Enable.
¾ Application Layer Gateway (ALG): It is recommended to enable Application Layer Gateway
(ALG) because ALG allows customized Network Address Translation (NAT) traversal filters to
be plugged into the gateway to support address and port translation for certain application
layer "control/data" protocols such as FTP, TFTP etc.
• FTP ALG: To allow FTP clients and servers to transfer data across NAT, click Enable.
• TFTP ALG: To allow TFTP clients and servers to transfer data across NAT, click
Enable.
• H323 ALG: To allow H323 clients and servers to transfer data across NAT, click
Enable.
• SIP ALG: To allow SIP clients and servers to transfer data across NAT, click Enable.
Click the Save button to save your settings.
4.5.7 DSL Settings
Choose “Advanced Setup”Æ“DSL Settings”, you can select the DSL Modulation Type and
Annex Type in the next screen. The DSL feature can be selected when you meet the physical
connection problem. Please check the proper settings with your Internet service provider.
Figure 4-20
¾ DSL Modulation Type: Select the DSL operation Modulation Type which your DSL
connection uses.
¾ Annex Type: Select the DSL operation Annex Type which your DSL connection uses.
Click the Save button to save your settings.
4.5.8 IPSec VPN
Choose “Network”Æ“IPSec VPN”, you can Add/Remove or Enable/Disable the IPSec tunnel
connections on the screen as shown in Figure 4-21.
