DNS Resolution
The process of translating a human-readable domain name (like example.com) into an IP address. DNS resolution involves recursive queries through a hierarchy of nameservers: root servers, TLD servers, and authoritative nameservers. DNS response codes (RCODEs) like NOERROR, NXDOMAIN, and SERVFAIL indicate the outcome of each query.
Related Protocols
Mentioned in Guides
Related Scenarios
511 Network Authentication Required — Captive Portal
HTTP
550 Domain Has No Mail — MX Record Missing
SMTP
NXDOMAIN — Domain Does Not Exist
DNS
SERVFAIL — DNS Server Failure
DNS
REFUSED — Recursive Query to Authoritative-Only Server
DNS
NXDOMAIN — Subdomain Typo or Missing DNS Record
DNS
SERVFAIL — Lame Delegation
DNS
FORMERR — Malformed DNS Query
DNS
High TTL Causing Delayed DNS Failover
DNS
NOTAUTH — Unauthorized DNS Dynamic Update
DNS
Defined In
RFC 1035
Domain Names - Implementation and Specification
RFC 1034
Domain Names - Concepts and Facilities
RFC 4035
Protocol Modifications for the DNS Security Extensions
RFC 8484
DNS Queries over HTTPS (DoH)
RFC 7858
Specification for DNS over Transport Layer Security (TLS)
RFC 3263
Session Initiation Protocol (SIP): Locating SIP Servers