Configuring Nat Translation Per Ip Interface - AudioCodes Mediant 4000 SBC User Manual

The figure below illustrates the NAT problem faced by SIP networks when the device is
located behind a NAT:

11.7.1.1 Configuring NAT Translation per IP Interface

The NAT Translation table lets you configure up to 32 network address translation (NAT)
rules for translating source IP addresses into NAT IP addresses (global - public) when the
device is located behind NAT. The device's NAT traversal mechanism replaces the source
IP address of SIP messages sent from a specific VoIP interface (Control and/or Media) in
the IP Interfaces table to a public IP address. This allows, for example, the separation of
VoIP traffic between different ITSPs and topology hiding of internal IP addresses from the
"public" network. Each IP network interface, configured in the IP Interfaces table can be
associated with a NAT rule, translating the source IP address and port of the outgoing
packet into the NAT address (IP address and port range).
The following procedure describes how to configure NAT translation rules through the Web
interface. You can also configure it through ini file (NATTranslation) or CLI (configure
network > nat-translation).

To configure NAT translation rules:
1. Open the NAT Translation table (Setup menu > IP Network tab > Core Entities
folder > NAT Translation).
User's Manual
Figure 11-5: Device behind NAT and NAT Issues
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Mediant 4000 SBC
Document #: LTRT-42025