11. DSR / Proxy Dual Mode Configuration

BalanceNG V4 allows a DSR / Proxy Dual Mode configuration, which is helpful to support local clients having difficulties operating with DSR (Direct Server Return) on the local LAN.

The DSR / Proxy Dual Mode Configuration is supported by BalanceNG V4 Release 4.009 and higher and works for IPv4 and IPv6 the same way.

The configuration is very easy and requires no special parameter setting.

To enable that feature, the virtual server needs “proxy enable” and the associated targets “dsr enable” at the same time.

The following rules apply with this configuration:

  • If a client is known to be on the local LAN (by BalanceNG), the proxy mode is used (acting as a TCP proxy).
  • If the client comes from external (forwarded by some router), the DSR mode is used.

Of course the DSR loopback aliases and the IPv4 ARP protection need to be in place as required for DSR (see Example 3 and Example 5 for further information and setup instructions).

Example partial configuration:

...
server    1 {
          ipaddr 10.31.40.43
          port 80
          protocol tcp
          proxy enable
          targets 1,2
}         
...
target    1 {
          ipaddr 10.31.40.80
          port 80
          protocol tcp
          dsr enable
}         
target    2 {
          ipaddr 10.31.40.81
          port 80
          protocol tcp
          dsr enable
}         
...