import { TypedEmitter } from '@n8n/backend-common';
import { SsrfProtectionConfig } from '@n8n/config';
import type { LookupAddress } from 'node:dns';
export type DnsCacheEventMap = {
    hit: undefined;
    miss: undefined;
    eviction: {
        size: number;
    };
};
export declare class InMemoryDnsCache {
    private readonly ssrfConfig;
    private cache;
    readonly events: TypedEmitter<DnsCacheEventMap>;
    constructor(ssrfConfig: SsrfProtectionConfig);
    private ensureCache;
    get size(): number;
    get(hostname: string): Promise<LookupAddress[] | undefined>;
    set(hostname: string, ips: LookupAddress[], ttl: number): Promise<void>;
    clear(): Promise<void>;
}