import type { MxRecord } from 'node:dns';
import { type Socket } from 'node:net';
import { type Target } from './address.js';
import { DNSResolver } from './resolver.js';
import type { CustomKVRecord, CustomRecord, DKIM1Record, DMARC1Record, SPF1Record, STSv1Record } from './txt-record.js';
import { TXTResult } from './txt-record.js';
import type { DomainCheckerOptions, ResolveOptions } from './types/options.js';
export type { MxRecord, Socket, DomainCheckerOptions, ResolveOptions };
export declare class DomainChecker {
    private options;
    private resolver;
    private failoverResolvers;
    constructor(options?: DomainCheckerOptions);
    private getParentDomain;
    getNsResolver(target: Target): Promise<DNSResolver>;
    hasMxRecord(target: Target): Promise<boolean>;
    private cleanMxRecord;
    getMxRecord(resolveOptions: ResolveOptions): Promise<MxRecord[]>;
    private resolveMxWithFailover;
    getNameServers(target: Target): Promise<string[]>;
    getSmtpConnection(target: Target): Promise<Socket | null>;
    private connectToSmtp;
    getCustomRecords(resolveOptions: ResolveOptions): Promise<CustomRecord[] | null>;
    getCustomKVRecord(resolveOptions: ResolveOptions, key: string): Promise<CustomKVRecord | null>;
    getAllKVRecords(resolveOptions: ResolveOptions): Promise<CustomKVRecord[] | null>;
    getSpfRecord(resolveOptions: ResolveOptions): Promise<SPF1Record | null>;
    private get_dkim_addr;
    getDkimRecord(resolveOptions: ResolveOptions): Promise<DKIM1Record | null>;
    private get_dmarc_addr;
    getDmarcRecord(resolveOptions: ResolveOptions): Promise<DMARC1Record | null>;
    private get_sts_addr;
    getStsRecord(resolveOptions: ResolveOptions): Promise<STSv1Record | null>;
    getTxtRecord(resolveOptions: ResolveOptions): Promise<TXTResult | null>;
    private getTxtRecordWithFailover;
}