Postel’s law
E121260
design principle
network protocol design principle
robustness principle
software engineering principle
Postel’s law is a design principle in computing and networking that advises systems to be conservative in what they send and liberal in what they accept, promoting robustness and interoperability.
All labels observed (3)
| Label | Occurrences |
|---|---|
| Postel’s law canonical | 2 |
| Postel principle | 1 |
| Postel’s robustness principle | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T1054611 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Postel’s law Context triple: [Jon Postel, knownFor, Postel’s law]
-
A.
Occam's razor
Occam's razor is a philosophical and scientific principle that advises preferring the simplest explanation that adequately accounts for all observed facts.
-
B.
Code and Other Laws of Cyberspace
Code and Other Laws of Cyberspace is a seminal book by legal scholar Lawrence Lessig that explores how software code functions as a form of regulation shaping behavior and governance in the digital world.
-
C.
Rule 41
Rule 41 is a provision of the U.S. Federal Rules of Civil Procedure that governs the voluntary and involuntary dismissal of civil actions in federal court.
-
D.
Clarke's three laws
Clarke's three laws are a set of aphorisms about science and technology, most famously stating that "any sufficiently advanced technology is indistinguishable from magic."
-
E.
Leacock-Pennebaker
Leacock-Pennebaker was a pioneering American documentary film production company known for its influential cinéma vérité works in the 1960s.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Postel’s law Target entity description: Postel’s law is a design principle in computing and networking that advises systems to be conservative in what they send and liberal in what they accept, promoting robustness and interoperability.
-
A.
Occam's razor
Occam's razor is a philosophical and scientific principle that advises preferring the simplest explanation that adequately accounts for all observed facts.
-
B.
Code and Other Laws of Cyberspace
Code and Other Laws of Cyberspace is a seminal book by legal scholar Lawrence Lessig that explores how software code functions as a form of regulation shaping behavior and governance in the digital world.
-
C.
Rule 41
Rule 41 is a provision of the U.S. Federal Rules of Civil Procedure that governs the voluntary and involuntary dismissal of civil actions in federal court.
-
D.
Clarke's three laws
Clarke's three laws are a set of aphorisms about science and technology, most famously stating that "any sufficiently advanced technology is indistinguishable from magic."
-
E.
Leacock-Pennebaker
Leacock-Pennebaker was a pioneering American documentary film production company known for its influential cinéma vérité works in the 1960s.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
design principle
ⓘ
network protocol design principle ⓘ robustness principle ⓘ software engineering principle ⓘ |
| alsoKnownAs |
Postel’s law
ⓘ
surface form:
Postel principle
Robustness principle ⓘ |
| appliesTo |
API design
ⓘ
data format parsers ⓘ network protocol implementations ⓘ software interfaces ⓘ |
| associatedWith |
IP
ⓘ
RFC 761 ⓘ RFC 793 ⓘ Transmission Control Protocol ⓘ
surface form:
TCP
|
| contrastedWith | strict input validation principles ⓘ |
| coreIdea |
be conservative in what you send
ⓘ
be liberal in what you accept ⓘ |
| criticizedBy |
security engineers
ⓘ
standards designers favoring strictness ⓘ |
| criticizedFor |
contributing to protocol ossification
ⓘ
encouraging tolerance of invalid or ambiguous data ⓘ making security vulnerabilities more likely ⓘ |
| field |
computer networking
ⓘ
computing ⓘ software engineering ⓘ |
| goal |
increase tolerance of variation in inputs
ⓘ
promote interoperability ⓘ promote robustness ⓘ |
| hasConsequence |
can increase interoperability between imperfect implementations
ⓘ
can make protocol evolution harder ⓘ implementations may diverge from strict specifications ⓘ systems accept non‑conforming inputs ⓘ |
| influenced |
API backward compatibility practices
ⓘ
HTML parsing behavior ⓘ email protocol implementations ⓘ web protocol design ⓘ |
| influencedBy | robustness concerns in heterogeneous networks ⓘ |
| namedAfter | Jon Postel ⓘ |
| originContext | early Internet protocol design ⓘ |
| relatedConcept |
backward compatibility
ⓘ
fault tolerance ⓘ forgiving parsers ⓘ robustness ⓘ |
| timePeriod | late 1970s ⓘ |
| typicalFormulation | be conservative in what you send, be liberal in what you accept ⓘ |
| usedIn |
API and protocol design best practices
ⓘ
Internet engineering discussions ⓘ software architecture guidelines ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Postel’s law Description of subject: Postel’s law is a design principle in computing and networking that advises systems to be conservative in what they send and liberal in what they accept, promoting robustness and interoperability.
Referenced by (4)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
Postel principle