AudioCodes E-SBC User Manual page 389

CHAPTER 18 Core Entities
'SBC Operation Mode'
sbc-operation-mode
[IPGroup_SBCOperationMode]
Parameter
Mediant 1000 Gateway & E-SBC | User's Manual
Description
■ For security, it is recommended to classify SIP
dialogs based on Proxy Set only if the IP address of
the IP Group is unknown. In other words, if the Proxy
Set associated with the IP Group is configured with
an FQDN. In such cases, the device classifies
incoming SIP dialogs to the IP Group based on the
DNS-resolved IP address. If the IP address is
known, it is recommended to use a Classification
rule instead (and disable the Classify by Proxy Set
feature), where the rule is configured with not only
the IP address, but also with SIP message
characteristics to increase the strictness of the
classification process (see
Classification Rules).
The reason for preferring classification based on
Proxy Set when the IP address is unknown is that IP
address forgery (commonly known as IP spoofing) is
more difficult than malicious SIP message tampering
and therefore, using a Classification rule without an
IP address offers a weaker form of security. When
classification is based on Proxy Set, the Clas-
sification table for the specific IP Group is ignored.
■ If you have assigned the same Proxy Set to multiple
IP Groups, disable the parameter and instead, use
Classification rules to classify incoming SIP dialogs
to these IP Groups. If the parameter is enabled, the
device is unable to correctly classify incoming
INVITEs to their appropriate IP Groups.
■ Classification by Proxy Set occurs only if
classification based on the device's registration
database fails (i.e., the INVITE is not from a
registered user).
Defines the device's operational mode for the IP Group.
■ [-1] Not Configured = (Default)
■ [0] B2BUA = Device operates as a back-to-back
user agent (B2BUA), changing the call identifiers and
headers between the inbound and outbound legs.
■ [1] Call Stateful Proxy = Device operates as a
Stateful Proxy, passing the SIP message
transparently between inbound and outbound legs. In
other words, the same SIP dialog identifiers (tags,
Call-Id and CSeq) occur on both legs (as long as no
other configuration disrupts the CSeq
compatibleness).
■
For more information on B2BUA and Stateful Proxy
modes, see B2BUA and Stateful Proxy Operating
Modes.
Note: If configured, the parameter overrides the 'SBC
Operation Mode' parameter in the SRDs table.
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Configuring