Billion BiPAC 6300VNOZ, User Manual, Page: 75 / 120

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4.4.2.3 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 “EWAN”.
Service Index:
Associated to EWAN interface marking each EWAN service (0-7), to select which EWAN
service the DMZ and Virtual server are applied to.
Click
DMZ
or
Virtual Server
to move on to set the DMZ or Virtual Server parameters, which
are represented in the following scenario.