/**
 * Reputation check result information
 */
export interface IReputationResult {
    score: number;
    isSpam: boolean;
    isProxy: boolean;
    isTor: boolean;
    isVPN: boolean;
    country?: string;
    asn?: string;
    org?: string;
    blacklists?: string[];
    timestamp: number;
    error?: string;
}
/**
 * Reputation threshold scores
 */
export declare enum ReputationThreshold {
    HIGH_RISK = 20,// Score below this is considered high risk
    MEDIUM_RISK = 50,// Score below this is considered medium risk
    LOW_RISK = 80
}
/**
 * IP type classifications
 */
export declare enum IPType {
    RESIDENTIAL = "residential",
    DATACENTER = "datacenter",
    PROXY = "proxy",
    TOR = "tor",
    VPN = "vpn",
    UNKNOWN = "unknown"
}
/**
 * Options for the IP Reputation Checker
 */
export interface IIPReputationOptions {
    maxCacheSize?: number;
    cacheTTL?: number;
    dnsblServers?: string[];
    highRiskThreshold?: number;
    mediumRiskThreshold?: number;
    lowRiskThreshold?: number;
    enableLocalCache?: boolean;
    enableDNSBL?: boolean;
    enableIPInfo?: boolean;
}
/**
 * Class for checking IP reputation of inbound email senders
 */
export declare class IPReputationChecker {
    private static instance;
    private reputationCache;
    private options;
    private static readonly DEFAULT_DNSBL_SERVERS;
    private static readonly DEFAULT_OPTIONS;
    /**
     * Constructor for IPReputationChecker
     * @param options Configuration options
     */
    constructor(options?: IIPReputationOptions);
    /**
     * Get the singleton instance of the checker
     * @param options Configuration options
     * @returns Singleton instance
     */
    static getInstance(options?: IIPReputationOptions): IPReputationChecker;
    /**
     * Reset the singleton instance (for shutdown/testing)
     */
    static resetInstance(): void;
    /**
     * Check an IP address's reputation
     * @param ip IP address to check
     * @returns Reputation check result
     */
    checkReputation(ip: string): Promise<IReputationResult>;
    /**
     * Check an IP against DNS blacklists
     * @param ip IP address to check
     * @returns DNSBL check results
     */
    private checkDNSBL;
    /**
     * Get information about an IP address
     * @param ip IP address to check
     * @returns IP information
     */
    private getIPInfo;
    /**
     * Simplified method to determine country from IP
     * In a real implementation, this would use a geolocation database or service
     * @param ip IP address
     * @returns Country code
     */
    private determineCountry;
    /**
     * Simplified method to determine organization from IP
     * In a real implementation, this would use an IP-to-org database or service
     * @param ip IP address
     * @returns Organization name
     */
    private determineOrg;
    /**
     * Reverse an IP address for DNSBL lookups (e.g., 1.2.3.4 -> 4.3.2.1)
     * @param ip IP address to reverse
     * @returns Reversed IP for DNSBL queries
     */
    private reverseIP;
    /**
     * Create an error result for when reputation check fails
     * @param ip IP address
     * @param errorMessage Error message
     * @returns Error result
     */
    private createErrorResult;
    /**
     * Validate IP address format
     * @param ip IP address to validate
     * @returns Whether the IP is valid
     */
    private isValidIPAddress;
    /**
     * Log reputation check to security logger
     * @param ip IP address
     * @param result Reputation result
     */
    private logReputationCheck;
    /**
     * Persist a single IP reputation result to the database via CachedIPReputation
     */
    private persistReputationToDb;
    /**
     * Load persisted reputations from CachedIPReputation documents into the in-memory LRU cache
     */
    private loadCacheFromDb;
    /**
     * Get the risk level for a reputation score
     * @param score Reputation score (0-100)
     * @returns Risk level description
     */
    static getRiskLevel(score: number): 'high' | 'medium' | 'low' | 'trusted';
}
