Issue 6.0 NEC SL1100
9 - 44 IP Multiline Station (SIP)
A firewall must be configured to allow specific traffic from the Internet to pass
through onto the LAN. If an IP phone is deployed out over the Internet there is
a very good chance it is passing through a firewall, either at the MAIN, the
remote, or both locations.
The following diagram shows two IP phones on the corporate local LAN and
one IP phone on a Remote network connected via the Internet. The two
phones that are installed on the local LAN are functioning correctly. The IP
phone at the remote site cannot register therefore it is not working.
The green arrow in the diagram above represents the data packets leaving the
IP phone destined for the SL1100 on the Headquarters LAN. The firewall on
the Headquarters network is not configured to recognize the UDP ports used
by the NEC equipment thus blocking them and resulting in registration failure.
To solve this issue the ports used by the NEC VoIP equipment must be
opened in the firewall allowing the NEC traffic to pass through onto the
SL1100.
The ports that are required to be opened on the headquarters locations are:
5080 and 5081 (UDP) for Signaling and 10020 ~ 10083 (UDP) for Voice.
The ports that need to be opened on the Remote network are 5060 (UDP) for
signaling and ports 3462 and 3463 for voice (UDP).
VPN
Another common feature is the use of the Internet as the WAN between
customer locations. When this is done VPNs are typically used between the
locations. A VPN (Virtual Private Network) is a private data network that
maintains privacy through the use of tunneling protocols and security features
over the public Internet. This allows for remote networks (with private
addresses), residing behind NAT routers and/or firewalls, to communicate
Figure 9-23 NEC SL1100 Network Example No. 1
Internet
Headquarters
Local LAN
Remote Network
Firewall
Firewall
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