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[Vigor3900] How to do Server Load Balance?

Since firmware version 1.3.0, Vigor3900/2960 supports Server Load Balance which can open the same public port to different local IP addresses or different ports.
More precisely, with Server Load Balance, you can host multiple servers on the LAN side for the same service, the router will do load balance for inbound NAT sessions, and the load balance weight for each server can be configured.

Some network administrators or enterprises may set up more then one server to provide the same service, to avoid the risk that a single server may be overload with huge traffic and service request. This feature is helpful in this senario, network administrator can set up few servers in the local area nertwork, only need to provide one public IP and port info for clients on internet, Vigor3900/2960 will help to distribute the traffic.


You can refer to your server type to choose the corresponding scheduler.

  • Least Connected: It will choose which server should respond the inbound traffic by the weight every time.  But if you connected to A server, then disconnect/offline A server, you would able to connect to B server once the sessions on A been terminated. 
  • Source IP Based: Differ from Least connected, router will decide which server should respond by the weight, but the same source IP will always connect to the same server. 

To configure server load balance, please go to NAT >> Server Load Balance:

  1. Click Add
  2. Give a profile name and enable it
  3. Select the protocol of service
  4. Select WAN interface
  5. Enter the port will be opened to local server
  6. Select a scheduler type
  7. Click Add at Real Server to set the IPs, ports and weights of local servers

With above configuration, when 10 clients from different Internet IP are requesting port 80 service to 3900's WAN1 at the same time, 3 of them are redirected to Server_A(, 1 of them to Server_B and 6 of them to Server_C.


With above configuration,router will distribute the traffic every time, 3 of them are redirected to Server_A(, 1 of them to Server_B and 6 of them to Server_C.

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