AirLive RS-1000 - Manual (Page 125)

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Virtual Server
The Security Bandwidth Manager separates an enterprise’s Intranet and Internet into LAN
networks and WAN networks respectively. Generally speaking, in order to allocate enough
IP addresses for all computers, an enterprise assigns each computer a private IP address,
and converts it into a real IP address through Security
Bandwidth Manager’s NAT (Network
Address Translation) function. If a server providing service to the WAN networks is located
in the LAN networks, outside users can’t directly connect to the server by using the server’s
private IP address.
The Security Bandwidth Manager’s Virtual Server can solve this problem. A virtual server
has set the real IP address of the Security Bandwidth Manager’s WAN network interface to be
the Virtual Server IP. Through the virtual server feature, the Security Bandwidth Manager
translates the virtual server’s IP address into the private IP address of physical server in the
LAN network. When outside users on the Internet request connections to the virtual server,
the request will be forwarded to the private LAN server.
Virtual Server owns another feature known as one-to-many mapping. This is when one virtual
server IP address on the WAN interface can be mapped into 4 LAN network server private IP
addresses. This option is useful for Load Balancing, which causes the virtual server to
distribute data packets to each private IP addresses (which are the real servers). By sending
all data packets to all similar servers, this increases the server’s efficiency, reduces risks of
server crashes, and enhances servers’ stability.
How to use Virtual Server and mapped IP
Virtual Server and Mapped IP are part of the IP mapping scheme. By applying the incoming
policies, Virtual Server and IP mapping work similarly. They map real IP addresses to the
physical servers’ private IP addresses (which is opposite to NAT), but there are still some
differences: