Server Name Indication extension
E258090
The Server Name Indication (SNI) extension is a TLS protocol feature that allows a client to indicate the hostname it is trying to connect to at the start of the handshake so that the server can present the correct certificate for virtual hosting.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Server Name Indication extension canonical | 2 |
| TLS SNI extension | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T2359739 — 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: Server Name Indication extension Context triple: [RFC 3546, defines, Server Name Indication extension]
-
A.
ALPN (Application-Layer Protocol Negotiation)
ALPN (Application-Layer Protocol Negotiation) is a TLS extension that allows clients and servers to agree on which application-layer protocol (such as HTTP/2 or SPDY) to use over a secure connection during the TLS handshake.
-
B.
NPN (Next Protocol Negotiation)
NPN (Next Protocol Negotiation) is a now-deprecated TLS extension that allowed a client and server to agree on which application-layer protocol (such as SPDY or HTTP/2) to use over a secure connection.
-
C.
SSL
SSL (Secure Sockets Layer) is a cryptographic protocol designed to provide secure, encrypted communication over a computer network, commonly used to protect data transmitted between clients and servers.
-
D.
DNS over TLS
DNS over TLS is a security protocol that encrypts traditional DNS queries and responses using Transport Layer Security to protect user privacy and prevent eavesdropping or tampering.
-
E.
RFC 5246
RFC 5246 is the Internet Engineering Task Force (IETF) standard that specifies Transport Layer Security (TLS) version 1.2, a widely used protocol for securing communications over computer networks.
- 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: Server Name Indication extension Target entity description: The Server Name Indication (SNI) extension is a TLS protocol feature that allows a client to indicate the hostname it is trying to connect to at the start of the handshake so that the server can present the correct certificate for virtual hosting.
-
A.
ALPN (Application-Layer Protocol Negotiation)
ALPN (Application-Layer Protocol Negotiation) is a TLS extension that allows clients and servers to agree on which application-layer protocol (such as HTTP/2 or SPDY) to use over a secure connection during the TLS handshake.
-
B.
NPN (Next Protocol Negotiation)
NPN (Next Protocol Negotiation) is a now-deprecated TLS extension that allowed a client and server to agree on which application-layer protocol (such as SPDY or HTTP/2) to use over a secure connection.
-
C.
SSL
SSL (Secure Sockets Layer) is a cryptographic protocol designed to provide secure, encrypted communication over a computer network, commonly used to protect data transmitted between clients and servers.
-
D.
DNS over TLS
DNS over TLS is a security protocol that encrypts traditional DNS queries and responses using Transport Layer Security to protect user privacy and prevent eavesdropping or tampering.
-
E.
RFC 5246
RFC 5246 is the Internet Engineering Task Force (IETF) standard that specifies Transport Layer Security (TLS) version 1.2, a widely used protocol for securing communications over computer networks.
- F. None of above. chosen
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
TLS extension
ⓘ
protocol feature ⓘ |
| allows | client to specify the server name it is connecting to ⓘ |
| alsoKnownAs | SNI ⓘ |
| appliesTo | TLS client ⓘ |
| carriedIn | ClientHello message ⓘ |
| category | TLS extension for server name indication ⓘ |
| definedIn | RFC 6066 ⓘ |
| enables |
hosting providers to serve many domains from one IP
ⓘ
multiple HTTPS sites on a single IP address ⓘ server to select appropriate certificate ⓘ virtual hosting with TLS ⓘ |
| extensionTypeValue | 0 ⓘ |
| hasConstraint | server must support SNI to select correct certificate ⓘ |
| hasEffectIfUnsupported | server may present default certificate ⓘ |
| hasField |
host_name
ⓘ
server_name_list ⓘ server_name_type ⓘ |
| hasPurpose |
indicate server hostname during TLS handshake
ⓘ
support name-based virtual hosting over TLS ⓘ |
| hasSuccessor | Encrypted Client Hello ⓘ |
| identifiedBy | TLS extension type server_name ⓘ |
| improves | certificate selection for multi-tenant servers ⓘ |
| introducedIn | TLS 1.0 era ⓘ |
| originallyDefinedIn | RFC 3546 ⓘ |
| partOf |
TLS protocol
ⓘ
TLS ⓘ
surface form:
Transport Layer Security
|
| privacyConsideration | allows passive observers to learn target hostname ⓘ |
| processedBy | TLS server ⓘ |
| relatedTo |
HTTPS
ⓘ
TLS certificate management ⓘ name-based virtual hosting ⓘ |
| requiredBy | many modern HTTPS virtual hosting configurations ⓘ |
| securityProperty | exposes requested hostname in cleartext in ClientHello ⓘ |
| standardizedBy |
Internet Engineering Task Force
ⓘ
surface form:
IETF
|
| supportsNameType | host_name ⓘ |
| usableWith |
TLS 1.0
ⓘ
TLS 1.1 ⓘ TLS 1.2 ⓘ TLS 1.3 ⓘ |
| usedBy |
HTTPS clients
ⓘ
TLS client libraries ⓘ content delivery networks ⓘ reverse proxies ⓘ web browsers ⓘ |
| usedInPhase | TLS handshake ⓘ |
| usesEncoding | ASCII for DNS hostnames ⓘ |
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: Server Name Indication extension Description of subject: The Server Name Indication (SNI) extension is a TLS protocol feature that allows a client to indicate the hostname it is trying to connect to at the start of the handshake so that the server can present the correct certificate for virtual hosting.
Referenced by (3)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
TLS SNI extension