RFC 2821
E210669
RFC 2821 is an earlier Internet standard that defined the Simple Mail Transfer Protocol (SMTP) for email transmission before being superseded by RFC 5321.
All labels observed (3)
| Label | Occurrences |
|---|---|
| RFC 2821 canonical | 7 |
| SMTP RFC 2821 | 1 |
| Simple Mail Transfer Protocol (SMTP) specification in RFC 2821 | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T1866841 — 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: RFC 2821 Context triple: [RFC 5321, obsoletes, RFC 2821]
-
A.
RFC 5321
RFC 5321 is the Internet standard that specifies the Simple Mail Transfer Protocol (SMTP) used for email transmission across IP networks.
-
B.
RFC 821
RFC 821 is the original Internet standard that formally defined the Simple Mail Transfer Protocol (SMTP) for electronic mail transmission.
-
C.
RFC 822
RFC 822 is an early Internet standard that defines the format of text-based email messages, including headers and addressing conventions.
-
D.
RFC 5322
RFC 5322 is the Internet standard that defines the syntax and format of text-based email messages, including headers such as From, To, Subject, and Date.
-
E.
RFC 3501
RFC 3501 is the Internet standard specification that defines version 4rev1 of the Internet Message Access Protocol (IMAP) used for accessing and managing email on a mail server.
- 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: RFC 2821 Target entity description: RFC 2821 is an earlier Internet standard that defined the Simple Mail Transfer Protocol (SMTP) for email transmission before being superseded by RFC 5321.
-
A.
RFC 5321
RFC 5321 is the Internet standard that specifies the Simple Mail Transfer Protocol (SMTP) used for email transmission across IP networks.
-
B.
RFC 821
RFC 821 is the original Internet standard that formally defined the Simple Mail Transfer Protocol (SMTP) for electronic mail transmission.
-
C.
RFC 822
RFC 822 is an early Internet standard that defines the format of text-based email messages, including headers and addressing conventions.
-
D.
RFC 5322
RFC 5322 is the Internet standard that defines the syntax and format of text-based email messages, including headers such as From, To, Subject, and Date.
-
E.
RFC 3501
RFC 3501 is the Internet standard specification that defines version 4rev1 of the Internet Message Access Protocol (IMAP) used for accessing and managing email on a mail server.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
Internet standard
ⓘ
Request for Comments ⓘ SMTP specification ⓘ |
| area | Applications Area ⓘ |
| category | Standards Track ⓘ |
| defaultPort |
25
ⓘ
587 ⓘ |
| definesAbbreviation | SMTP ⓘ |
| definesCommand |
DATA
ⓘ
EHLO ⓘ EXPN ⓘ HELO ⓘ MAIL ⓘ NOOP ⓘ QUIT ⓘ RCPT ⓘ RSET ⓘ TURN ⓘ VRFY ⓘ |
| definesProtocol |
Simple Mail Transfer Protocol
ⓘ
linked to:
SMTP
|
| obsoletedBy | RFC 5321 ⓘ |
| obsoletes |
RFC 1651
ⓘ
RFC 1652 ⓘ RFC 1869 ⓘ RFC 1870 ⓘ RFC 2197 ⓘ RFC 821 ⓘ RFC 974 ⓘ |
| protocolLayer | application layer ⓘ |
| publishedBy |
IETF
ⓘ
linked to:
Internet Engineering Task Force
Internet Engineering Task Force ⓘ |
| relatedTo |
RFC 2822
ⓘ
RFC 5321 ⓘ |
| RFCNumber | 2821 ⓘ |
| specifies |
SMTP commands
ⓘ
SMTP envelope format ⓘ SMTP replies ⓘ SMTP session model ⓘ error handling for SMTP ⓘ forwarding and relaying rules ⓘ mail queueing behavior ⓘ mail routing via MX records ⓘ retry strategies for message delivery ⓘ use of domain names in SMTP ⓘ |
| standardizes | email transmission ⓘ |
| status | Obsoleted ⓘ |
| title |
Simple Mail Transfer Protocol
ⓘ
linked to:
SMTP
|
| transportProtocol | TCP ⓘ |
| updates | SMTP model from RFC 821 ⓘ |
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: RFC 2821 Description of subject: RFC 2821 is an earlier Internet standard that defined the Simple Mail Transfer Protocol (SMTP) for email transmission before being superseded by RFC 5321.
Referenced by (9)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: RFC 2821
linked to: RFC 2821