/**
 * MTA error classes for SMTP client operations
 */
export declare class MtaConnectionError extends Error {
    code: string;
    details?: any;
    constructor(message: string, detailsOrCode?: any);
    static timeout(host: string, port: number, timeoutMs?: number): MtaConnectionError;
    static refused(host: string, port: number): MtaConnectionError;
    static dnsError(host: string, err?: any): MtaConnectionError;
}
export declare class MtaAuthenticationError extends Error {
    code: string;
    details?: any;
    constructor(message: string, detailsOrCode?: any);
    static invalidCredentials(host?: string, user?: string): MtaAuthenticationError;
}
export declare class MtaDeliveryError extends Error {
    code: string;
    responseCode?: number;
    details?: any;
    constructor(message: string, detailsOrCode?: any, responseCode?: number);
    static temporary(message: string, ...args: any[]): MtaDeliveryError;
    static permanent(message: string, ...args: any[]): MtaDeliveryError;
}
export declare class MtaConfigurationError extends Error {
    code: string;
    details?: any;
    constructor(message: string, detailsOrCode?: any);
}
export declare class MtaTimeoutError extends Error {
    code: string;
    details?: any;
    constructor(message: string, detailsOrCode?: any);
    static commandTimeout(command: string, hostOrTimeout?: any, timeoutMs?: number): MtaTimeoutError;
}
export declare class MtaProtocolError extends Error {
    code: string;
    details?: any;
    constructor(message: string, detailsOrCode?: any);
}