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What is the real maximum length of a DNS name? (2012)

The article clarifies that the maximum DNS name length is 255 octets, not characters, explaining the binary label-based encoding format defined in RFC 1035. It resolves a common confusion where names appearing under the character limit are rejected due to octet encoding overhead from length prefixes and root termination.

Background

DNS (Domain Name System) is a core internet infrastructure protocol that resolves domain names to IP addresses. RFC 1035 remains the foundational specification for DNS message formats and encoding.

Source
Lobsters
Published
Sep 1, 2026 at 01:16 AM
Score
6.0 / 10