import { type Target } from './address.js';
export interface MtaStsPolicy {
    version: string;
    mode: 'enforce' | 'testing' | 'none';
    mx: string[];
    max_age: number;
}
export declare function getMtaStsPolicy(target: Target): Promise<MtaStsPolicy | null>;
export declare function isMxAllowed(mxHost: string, policy: MtaStsPolicy): boolean;