/**
 * Resolves a hostname to the IP addresses it currently maps to. Throwing (or
 * rejecting) refuses the request.
 */
export type HostResolver = (host: string) => Promise<string[]>;
export declare function isAllowedAddress(ip: string): boolean;
export declare function hostForResolution(url: URL): string;
export declare function assertAllowedDatasourceUrl(url: URL): void;