SMC Networks SMCBR21VPN - Manual (Page 119)

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Chapter 10 Virtual Server
Virtual Server
The real IP address provided from ISP is always not enough for all the users
when the system manager applies the network connection from ISP. 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 SMC BR21VPN’s NAT (Network Address Translation)
function. If a server that provides service to WAN network is located in LAN
networks, external users cannot directly connect to the server by using the
server’s private IP address.
The SMC BR21VPN’s Virtual Server function can solve this problem. A Virtual
Server has set the real IP address of the SMC BR21VPN’s WAN network
interface to be the Virtual Server IP. Through the Virtual Server function, the
SMC BR21VPN translates the Virtual Server’s IP address into the private IP
address in the LAN network.
Virtual Server owns another feature know as one-to-many mapping. This is
when one real server IP address on the WAN interface can be mapped into four
LAN network servers provide the same service 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 session.
Therefore, it can reduce the loading of a single server and lower the crash risk.
And can improve the work efficiency.