Technical data

Table Of Contents

398 COMpact 3000 analog/ISDN/VoIP - Firmware Version 4.0 - Version of the Manual 03 02/11

Configuring and Managing the PBX

VoIP

Configuring External Private Branch Exchanges

In order to operate a VoIP telephone as an external private branch exchange, it must either be

connected to the network via a VPN tunnel or the telephone and the PBX must establish the

connection via a publicly accessible STUN server on the Internet and a DynDNS service as

described in the following.

Note:

Each port forwarding constitutes a security risk. You should use as few

forwarding configurations as possible.

Note that when using an external private branch exchange, emergency calls

can only be traced backed to the location of the connection used (locali-

zation). Localization is necessary if the caller is no longer able to give his

name and address. Therefore, for emergency calls from an external private

branch exchange, a mobile telephone or a telephone connected to the

public switched network is required.

For security reasons, the connection of external private branch exchanges

by means of a VPN tunnel should be preferred.

Important: As a protection measure against the access by third parties,

regularly check the call data recording of your PBX and the LOGs of your

NAT router for inconsistencies.

Requirements:

– VoIP channels (COMpact 3000 VoIP or VoIP channels purchased and activated in the

Upgrade Center)

– Portforwarding configured on router

Configure the PBX as follows if at least one external private branch exchange is not coupled

over a VPN tunnel:

1. Configure a VoIP channel as an internal VoIP channel for each external private branch

exchange planned.

2. Create the internal telephone numbers for the external private branch exchanges (a

maximum of two VoIP subscribers is recommended).

3. If necessary, assign user PINs for the external private branch exchanges (recom-

mended). These PINs are required for authenticating the VoIP telephones when they

are registered on the PBX.