Auerswald COMpact 4000 Operation Manual page 598

Settings
VoIP
VoIP Provider Settings
RTP
SRTP
Requirements:
• external VoIP channel that supports SRTP (optional, see Important Information > Product
Details > Basic Assembly and Extensions section)
Disabled: Forces disabling of call data encryption by SRTP. The connection is not established
if the call partner (VoIP provider, other PBX in sub-system operation or external VoIP
subscriber) requires call data to be encrypted using SRTP.
preferred: Switches on negotiation for the encryption of call data by SRTP. When a call is
made, the call partner will be asked if encryption is possible. If so, the call data will be encrypted
and then transmitted, if not, the call data will not be encrypted.
required: Forces enabling of call data encryption by SRTP. The connection is not established
if the call partner (VoIP provider, other PBX in sub-system operation or external VoIP
subscriber) does not require call data to be encrypted using SRTP.
Note: SIPS should also be enabled at the same time, otherwise the key for
SRTP encryption would be readable.
NAT traversal
NAT (Network Address Translation) enables you to convert a particular IP address that is used
within a network (e.g. a local network) into a different IP address that can be used by a different
network (e.g. the public switched telephone network). If NAT traversal is switched on, and a
query is sent from a local IP address to the public network, the sending IP address is swapped
with the public IP address. This function is performed in the reverse direction for the reply.
Disabled: NAT traversal is not performed by the PBX. The router which connects the local area
network with the Internet should be a properly functioning, SIP-aware router which performs
NAT traversal.
Enabled with use of STUN: NAT traversal is performed by the PBX. To achieve this, a STUN
server must also be specified for the VoIP provider.
Caution: Each time a port is opened on the NAT router, this creates a
potential source of danger.
• It is essential you put additional protective measures in place.
598
COMpact 4000 - Firmware V6.6A - Installation, Operation and Configuration V03 03/2016