AudioCodes Mediant 500 MSBR, User Manual

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Version 7.2 143 Mediant 500 MSBR
User's Manual 15. Network
Source Interface
src-interface-name
[NATTranslation_SrcI
PInterfaceName]
Assigns an IP network interface to the rule. Outgoing packets sent from the
specified network interface are NAT'ed.
By default, no value is defined.
Source Start Port
src-start-port
[NATTranslation_Sour
ceStartPort]
Defines the optional starting port range (0-65535) of the IP interface, used
as matching criteria for the NAT rule. If not configured, the match is done
on the entire port range. Only IP addresses and ports of matched source
ports will be replaced.
Source End Port
src-end-port
[NATTranslation_Sour
ceEndPort]
Defines the optional ending port range (0-65535) of the IP interface, used
as matching criteria for the NAT rule. If not configured, the match is done
on the entire port range. Only IP addresses and ports of matched source
ports will be replaced.
Target
Target IP Address
target-ip-address
[NATTranslation_Targ
etIPAddress]
Defines the global (public) IP address. The device adds the address in the
outgoing packet to the SIP Via header, Contact header, 'o=' SDP field, and
'c=' SDP field.
Target Start Port
target-start-port
[NATTranslation_Targ
etStartPort]
Defines the optional starting port range (0-65535) of the global address. If
not configured, the ports are not replaced. Matching source ports are
replaced with the target ports. This address is set in the SIP Via and
Contact headers and in the 'o=' and 'c=' SDP fields.
Target End Port
target-end-port
[NATTranslation_Targ
etEndPort]
Defines the optional ending port range (0-65535) of the global address. If
not configured, the ports are not replaced. Matching source ports are
replaced with the target ports. This address is set in the SIP Via and
Contact headers and in the 'o=' and 'c=' SDP fields.
15.2.2 Remote UA behind NAT
This section describes configuration for scenarios where the device sends signaling and
media packets to a remote UA that is located behind NAT.
15.2.2.1 SIP Signaling Messages
By default, the device resolves NAT issues for SIP signaling, using its NAT Detection
mechanism. The NAT Detection mechanism checks whether the endpoint is located behind
NAT by comparing the source IP address of the incoming UDP/TCP packet (in which the
SIP message is received) with the IP address in the SIP Contact header. If the packet's
source IP address is a public address and the Contact header's IP address is a local
address, the device considers the endpoint as located behind NAT. In this case, the device
sends the SIP messages to the endpoint using the packet's source IP address. Otherwise
(or if you have disabled the NAT Detection mechanism), the device sends the SIP
messages according to the SIP standard (RFC 3261), where requests within the SIP dialog
are sent using the IP address in the Contact header and responses to INVITEs are sent
using the IP address in the Via header.
If necessary, you can also configure the device to always consider incoming SIP INVITE
messages as sent from endpoints that are located behind NAT. When this is enabled, the