DNS cache
A DNS cache is temporary storage of domain-name resolution results used to answer subsequent lookups without repeating upstream DNS queries.
Acing the CCNA Exam: Volume 2 Advanced Networking and Security
DNS caching is the temporary storage of DNS answers so subsequent name-resolution requests can be answered without repeating all queries.
- How it is used
- Speeds name resolution by reusing previously resolved addresses instead of repeating DNS queries.
- How deep it goes
- Explains cache hits, misses, storage, multiple cache levels, and recursive-resolution caching, with command output but no cache-management internals.
- Examples
- Uses browser lookups, www.google.com, mail.google.com, Windows ipconfig /displaydns, and Cisco IOS show hosts output.
- What you can do after
- Diagnose with ipconfig /displaydns or show hosts whether a hostname-to-address mapping is cached.
Read how Acing the CCNA Exam: Volume 2 Advanced Networking and Security explains DNS cache →
Grokking Web Application Security
A DNS cache is stored DNS resolution data retained temporarily to answer repeated lookups without querying upstream servers.
- How it is used
- Supports scalable DNS resolution while providing attack surfaces for traffic redirection.
- How deep it goes
- Explains caching across browser, operating-system, ISP, and corporate layers, but does not detail cache implementation.
- Examples
- Uses browser memory, operating-system and ISP caches, host-file paths, and a Swedish ISP compromise as examples.
- What you can do after
- Evaluate DNS-poisoning exposure by locating cache layers and applying HTTPS as a protective control.
Read how Grokking Web Application Security explains DNS cache →
Related concepts
- Mapuses · A map is an associative data structure that stores key-value pairs and supports retrieving values by key.
- domain name systemused by · The Domain Name System is a distributed, hierarchical naming system that resolves domain names to IP addresses and other network resource records.
- DNS poisoningused by · DNS poisoning is an attack that corrupts name-resolution data so requests are directed to malicious or incorrect network destinations.
- dns querycontrasts with · A DNS query is a request sent to the Domain Name System to obtain information about a domain name or other DNS record.
- DNS serverused by · A DNS server is a network service that answers domain-name queries by returning corresponding DNS records or obtaining them from other DNS servers.
These guides are generated from the text of Manning books by Manning's knowledge graph and link to the sections they draw on. The full books are available on liveBook and at manning.com.