NAT
The NAT (Network Address Translation) feature transforms a private IP into a public IP, allowing
multiple users to access the internet through a single IP account, sharing the single IP address. NAT
break the originally envisioned model of IP end-to-end connectivity across the internet so NAT can
cause problems where IPSec/ PPTP encryption is applied or some application layer protocols such as
SIP phones are located behind a NAT. And NAT makes it difficult for systems behind a NAT to accept
incoming communications.
In this session, there are "VPN Passthrough", "SIP ALG", "DMZ" and "Virtual Server" provided to solve
these nasty problems.
NAT Status: Enabled. It depends on ISP Connection Type in Internet settings.
VPN Passthrough: VPN pass-through is a feature of routers which allows VPN client on a private
network to establish outbound VPNs unhindered.
SIP ALG: Enable the SIP ALG when SIP phone needs ALG to pass through the NAT. Disable the SIP
ALG when SIP phone includes NAT-Traversal algorithm.
Interface: Select to set DMZ/Virtual Server for "3G/4G-LTE" or "EWAN".
Click DMZ
or Virtual Server
to move on to set the DMZ or Virtual Server parameters,
which are represented in the following scenario.