VoIP > Settings

The SonicWALL security appliance allows VoIP phone and applications to be deployed behind the firewall. The VoIP > Settings page includes the settings for supporting VoIP traffic on the SonicWALL security appliance.

Voice over IP (VoIP) protocols is a term used in IP telephony for a set of facilities for managing the delivery of voice information using IP. In general, this means sending voice information in digital form in discrete packets rather than in the traditional circuit protocols of the public switched telephone network (PSTN). A major advantage of VoIP and Internet telephony is that it avoids the tolls charged by traditional telephone service.

The SonicWALL security appliance supports the most widely used VoIP standard protocols and the most commonly used VoIP vendors and systems on the market. Providing full VoIP support on the SonicWALL security appliance enables organizations with increasingly decentralized workforces to access corporate voice services from remote sites. VoIP systems consist of multiple clients (such as IP phones or soft phones) and VoIP servers residing at different parts of the network.

VoIP Protocols

This section provides a concept overview on H.323 and SIP protocols. Refer to the “Configuring the VoIP Settings” section for configuration tasks for H.323 and SIP networks.


H.323 is a comprehensive suite of protocols for voice, video, and data communications between computers, terminals, network devices, and network services. H.323 is designed to enable users to make point-to-point multimedia phone calls over connectionless packet-switching networks such as private IP networks and the Internet.

H.323 is widely supported by manufacturers of video conferencing equipment, VoIP equipment and Internet telephony software and devices.

An H.323 network consists of four different types of entities:


Session Initiation Protocol (SIP) is a signaling protocol used in VoIP. Using SIP, a VoIP client can initiate and terminate call sessions, invite members into a conferencing session, and perform other telephony tasks. SIP also enables Private Branch Exchanges (PBXs), VoIP gateways, and other communications devices to communicate in standardized collaboration. SIP was also designed to avoid the heavy overhead of H.323.

General Settings

The Consistent NAT setting ensures predictable re-use of the same translated IP address and UDP port pair for internal (LAN) address and port pairs. This checkbox is disabled by default. Consistent NAT changes standard NAT policy to provide greater compatibility with peer-to-peer applications that require a consistent IP address to connect to, such as Apple’s iChat, and certain online games. Consistent NAT uses an MD5 hashing method to consistently assign the same mapped public IP address and UDP Port pair to each internal private IP address and port pair.

SIP Settings

This section provides configuration tasks for SIP Settings.

H.323 Settings

This section provides configuration tasks for H.323 Settings.

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