@Override
    NettyConnection createNettyConnection(ChannelHandlerContext ctx) {
        final PacketDeliverer backupDeliverer = BACKUP_PACKET_DELIVERY_ENABLED.getValue() ? XMPPServer.getInstance().getPacketDeliverer() : null;
        return new NettyConnection(ctx, backupDeliverer, configuration);
    }
Enable / disable backup delivery of stanzas to the XMPP server itself when a stanza failed to be delivered on a
server-to-server connection. When disabled, stanzas that can not be delivered on the connection are discarded.
xmppserver/src/main/java/org/jivesoftware/openfire/nio/NettyServerConnectionHandler.java