MASTER parameter*   ==  MASTER=host:port[/masterControl][:dstHostList]
                    --  default: none

This parameter specifies an upstream generalist DeleGate (MASTER-DeleGate) to which this DeleGate will forward requests. Forwarding to a MASTER-DeleGate can be filtered by postfixing ":dstHostList"; only request toward destination servers listed in dstHostList are forwarded to the MASTER-DeleGate. When multiple MASTERs are given, they are tried in order until connection to a MASTER succeed.

Optional "/masterControl" can be:

cache -- use the MASTER only if cache hits in the MASTER
teleport -- make a persistent Teleport connection to the MASTER