src/connectivity/network/netstack3/sysmgr/netstack3.config

{
    "services": {
        "fuchsia.net.stack.Stack": "fuchsia-pkg://fuchsia.com/netstack3#meta/netstack3.cmx",
        "fuchsia.posix.socket.Provider": "fuchsia-pkg://fuchsia.com/netstack3#meta/netstack3.cmx"
    }
}