AltiGen MAXCS 7.0 Update 1 ACM Administration - Manual (Page 319)

Network Using NAT
MaxCS 7.5 Administration Manual 303
Network Using NAT
You are probably using NAT if both of the following conditions apply:
• Your MAXCS ACM server's IP address matches any of the following numbers (where x is any number
from 0-255):
• 10.x.x.x
• 172.16.x.x to 172.32.x.x
• 192.168.x.x
• You are able to connect to the Internet directly without using a proxy server.
• Contact your router/firewall vendor to obtain a software update for your networking equipment, or obtain
routable address space from your Internet provider. If you are unsure whether or not you are using NAT,
contact your router/firewall vendor or Internet provider.
Network Configuration Guidelines for AltiGen IP Phones
The following guidelines (specific to AltiGen IP phones) should be taken into consideration before you config-
ure your network for use with NAT.
• DHCP is recommended to reduce the risks for duplicating IP addresses. MAXCS provides seamless
support for AltiGen IP phones using dynamic IP addresses. Select Dynamic IP address for IP Extensions
in the Max Admin’s Extension Configuration window.
• A switch is required; VoIP quality can be adversely affected if a hub is used.
We recommend the following settings on the MaxCS server:
• Large Send Offload VZ (IPv4) – Disable
• Receive Side Scaling – Disable
• IP Security (IPSec) Offload – Disable
• TCP Checksum Offload IPv4 – Disable
• UDP Checksum Offload IPv4 – Disable
Configuration Guidelines for NAT
Note: This section applies only to AltiGen IP phones or IPTalk integrated with MaxCommunicator or
MaxAgent.
The section discusses the configuration guidelines when MAXCS is behind NAT (Network Address
Translation) and communication to AltiGen IP phones, IPTalk, or another MAXCS is over WAN. AltiGen SIP
phones support NAT traversal, which does not require special settings on the NAT router at the remote site.
Due to SIP protocol, which puts the IP address information in the TCP/IP payload, the NAT router requires
some SIP protocol implementation to correctly handle the SIP traffic and translate the private IP address into
a public IP address. Not all NAT routers have this kind of implementation, or have it implemented correctly (SIP
ALG). If the NAT router does not support SIP ALG properly, you need to check Enable SIP NAT Support and
Enable SIP NAT Support
in Enterprise Manager on the IP Networks tab. Also, SIP ALG must be disabled in
the NAT router to avoid the conflict between SIP ALG and SIP NAT support provided by MaxCS..
The following sections illustrate a private network configuration and a VPN configuration.
For information on setting up VoIP traffic forwarding for NAT and configuring MAXCS behind NAT, see
“Configuring MAXCS Behind NAT” on page 321.