List of RFCs

This is a partial list of RFCs (request for comments memoranda). A Request for Comments (RFC) is a publication in a series from the principal technical development and standards-setting bodies for the Internet, most prominently the Internet Engineering Task Force (IETF).

While there are over 9,151 RFCs as of February 2022, this list consists of RFCs that have related articles. A complete list is available from the IETF website.

Numerical list

#	Title	Date published	Related article	Made obsolete by	Notes
RFC 20	ASCII format for Network Interchange	October 16, 1969	ASCII
RFC 42	Message Data Types	31 March 1970
RFC 768	User Datagram Protocol	August 28, 1980	UDP
RFC 783	THE TFTP PROTOCOL (REVISION 2)	June 1981	TFTP	RFC 1350
RFC 791	Internet Protocol	September 1981	IPv4
RFC 792	INTERNET CONTROL MESSAGE PROTOCOL	September 1981	ICMP
RFC 793	TRANSMISSION CONTROL PROTOCOL	September 1981	TCP	RFC 9293
RFC 826	An Ethernet Address Resolution Protocol	November 1982	ARP
RFC 854	TELNET PROTOCOL SPECIFICATION	May 1983	Telnet
RFC 855	TELNET OPTION SPECIFICATIONS	May 1983
RFC 862	Echo Protocol	May 1983	Echo
RFC 863	Discard Protocol	May 1983	DISCARD
RFC 864	Character Generator Protocol	May 1983	CHARGEN
RFC 868	Time Protocol	May 1983	TIME
RFC 903	A Reverse Address Resolution Protocol	June 1984	RARP
RFC 937	POST OFFICE PROTOCOL - VERSION 2	February 1985	POP v 2
RFC 951	BOOTSTRAP PROTOCOL (BOOTP)	September 1985	BOOTP
RFC 959	FILE TRANSFER PROTOCOL (FTP)	October 1985	FTP
RFC 1034	DOMAIN NAMES - CONCEPTS AND FACILITIES	November 1987	DNS
RFC 1035	DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION	November 1987	DNS
RFC 1036	Standard for Interchange of USENET Messages	December 1987	Usenet
RFC 1055	A Non-Standard for Transmission of IP Datagrams Over Serial Lines: SLIP	June 1988	SLIP
RFC 1058	Routing Information Protocol	June 1988	RIP v 1
RFC 1059	Network Time Protocol (version 1) specification and implementation	July 1988	NTP v 1
RFC 1087	Ethics and the Internet	January 1989	Internet Ethics
RFC 1118	The Hitchhikers Guide to the Internet	September 1989	The Hitchhikers Guide to the Internet
RFC 1119	Network Time Protocol (version 2) specification and implementation	September 1989	NTP v 2
RFC 1149	A Standard for the Transmission of IP Datagrams on Avian Carriers	April 1, 1990	IP over Avian Carriers
RFC 1157	A Simple Network Management Protocol (SNMP)	May 1990	SNMP v1
RFC 1176	INTERACTIVE MAIL ACCESS PROTOCOL - VERSION 2	August 1990	IMAP v 2
RFC 1305	Network Time Protocol (Version 3) Specification, Implementation and Analysis	March 1992	NTP v 3	RFC 5905	Obsoletes RFC 1119, RFC 1059, RFC 958
RFC 1321	The MD5 Message-Digest Algorithm	April 1992	MD5
RFC 1350	THE TFTP PROTOCOL (REVISION 2)	July 1992	TFTP		Obsoletes RFC 783
RFC 1436	The Internet Gopher Protocol	March 1993	Gopher
RFC 1441	Introduction to version 2 of the Internet-standard Network Management Framework	April 1993	SNMP v 2
RFC 1459	Internet Relay Chat Protocol	May 1993	IRC
RFC 1730	INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4	December 1994	IMAP v 4
RFC 1777	Lightweight Directory Access Protocol	March 1995	LDAP
RFC 1855	Netiquette Guidelines	October 1995	Netiquette
RFC 1918	Address Allocation for Private Internets	February 1996	Private network
RFC 1928	SOCKS Protocol Version 5	March 1996	SOCKS5
RFC 1939	Post Office Protocol - Version 3	May 1996	POP v 3
RFC 1945	Hypertext Transfer Protocol—HTTP/1.0	May 1996	HTTP v 1.0
RFC 1948	Defending Against Sequence Number Attacks	May 1996	IP spoofing
RFC 1950	ZLIB Compressed Data Format Specification version 3.3	May 1996	Zlib v 3.3
RFC 1951	DEFLATE Compressed Data Format Specification version 1.3	May 1996	DEFLATE v 1.3
RFC 1952	GZIP file format specification version 4.3	May 1996	Gzip v 4.3
RFC 1964	The Kerberos Version 5 GSS-API Mechanism	June 1996	Kerberos; GSSAPI
RFC 2080	RIPng for IPv6	January 1997	RIP v ng
RFC 2119	Key words for use in RFCs to Indicate Requirement Levels	March 1997	Request for Comments		Updated by RFC 8174
RFC 2131	Dynamic Host Configuration Protocol	March 1997	DHCP
RFC 2177	IMAP4 IDLE command	June 1997	IMAP IDLE
RFC 2195	IMAP/POP AUTHorize Extension for Simple Challenge/Response	September 1997	CRAM-MD5
RFC 2228	FTP Security Extensions	October 1997	FTP
RFC 2230	Key Exchange Delegation Record for the DNS	November 1997	Secure DNS
RFC 2246	The TLS Protocol Version 1.0	January 1999	TLS 1.0
RFC 2251	Lightweight Directory Access Protocol (v3)	December 1997	LDAP v 3
RFC 2252	Lightweight Directory Access Protocol (v3): Attribute Syntax Definitions
RFC 2253	Lightweight Directory Access Protocol (v3): UTF-8 String Representation of Distinguished Names
RFC 2254	The String Representation of LDAP Search Filters
RFC 2255	The LDAP URL Format
RFC 2256	A Summary of the X.500(96) User Schema for use with LDAPv3
RFC 2326	Real Time Streaming Protocol (RTSP)	April 1998	RTSP
RFC 2327	SDP: Session Description Protocol	April 1998	SDP
RFC 2328	OSPF Version 2	April 1998	OSPF
RFC 2351	Mapping of Airline Reservation, Ticketing, and Messaging Traffic over IP	May 1998	MATIP
RFC 2362	Protocol Independent Multicast-Sparse Mode (PIM-SM)	June 1998	PIM
RFC 2397	The "data" URL scheme	August 1998	Data: URI scheme
RFC 2407	Internet IP Security Domain of Interpretation for ISAKMP.	November 1998	IKE
RFC 2408	Internet Security Association and Key Management Protocol (ISAKMP)
RFC 2409	The Internet Key Exchange (IKE)
RFC 2427	Multiprotocol Interconnect over Frame Relay	September 1998	Frame Relay	1294, 1490
RFC 2453	RIP Version 2	November 1998	RIP v 2
RFC 2460	Internet Protocol, Version 6 (IPv6) Specification	December 1998	IPv6	RFC 8200
RFC 2549	IP over Avian Carriers with Quality of Service	April 1, 1999	IP over Avian Carriers
RFC 2555	30 Years of RFCs	April 7, 1999			Retraces the history of RFCs
RFC 2570	Introduction to Version 3 of the Internet-standard Network Management Framework	April 1999	SNMP v3
RFC 2595	Using TLS with IMAP, POP3 and ACAP	June 1999	STARTTLS for IMAP, POP3 and ACAP
RFC 2606	Reserved Top Level DNS Names	June 1999	Fictitious domain name		example.com, .test, ...
RFC 2740	OSPF for IPv6	December 1999	OSPF
RFC 2743	Generic Security Service Application Program Interface Version 2, Update 1	January 2000	GSSAPI v 2
RFC 2744	Generic Security Service API Version 2 : C-bindings
RFC 2801	Internet Open Trading Protocol - IOTP Version 1.0	April 2000	Internet Open Trading Protocol
RFC 2802	Digital Signatures for the v1.0 Internet Open Trading Protocol (IOTP)	April 2000	Internet Open Trading Protocol
RFC 2810	Internet Relay Chat: Architecture	April 2000	IRC
RFC 2811	Internet Relay Chat: Channel Management
RFC 2812	Internet Relay Chat: Client Protocol
RFC 2813	Internet Relay Chat: Server Protocol
RFC 2853	Generic Security Service API Version 2 : Java Bindings	June 2000	GSSAPI v 2
RFC 2865	Remote Authentication Dial In User Service (RADIUS)	June 2000	RADIUS
RFC 2866	RADIUS Accounting	June 2000
RFC 2935	Internet Open Trading Protocol (IOTP) HTTP Supplement	September 2000	Internet Open Trading Protocol
RFC 2974	Session Announcement Protocol	October 2000	SAP
RFC 3504	Internet Open Trading Protocol (IOTP), Version 1, Errata	March 2003	Internet Open Trading Protocol
RFC 3022	Traditional IP Network Address Translator (Traditional NAT)	January 2001	NAT
RFC 3031	Multiprotocol Label Switching Architecture	January 2001	MPLS
RFC 3053	IPv6 Tunnel Broker	January 2001	Tunnel Broker
RFC 3056	Connection of IPv6 Domains via IPv4 Clouds	February 2001	6to4
RFC 3080	The Blocks Extensible Exchange Protocol Core	March 2001	BEEP
RFC 3162	RADIUS and IPv6	August 2001	RADIUS (IPv6)
RFC 3207	SMTP Service Extension for Secure SMTP over Transport Layer Security	February 2002	STARTTLS for SMTP
RFC 3261	SIP: Session Initiation Protocol	June 2002	SIP
RFC 3284	The VCDIFF Generic Differencing and Compression Data Format	June 2002	VCDIFF
RFC 3286	An Introduction to the Stream Control Transmission Protocol (SCTP)	May 2002	SCTP
RFC 3315	Dynamic Host Configuration Protocol for IPv6 (DHCPv6)	July 2003	DHCP (IPv6)
RFC 3339	Date and Time on the Internet: Timestamps	July 2002	Timestamp
RFC 3376	Internet Group Management Protocol, Version 3	October 2002	IGMP v 3
RFC 3401	Dynamic Delegation Discovery System (DDDS) Part One: The Comprehensive DDDS	October 2002	DDDS
RFC 3402	Dynamic Delegation Discovery System (DDDS) Part Two: The Algorithm
RFC 3403	Dynamic Delegation Discovery System (DDDS) Part Three: The Domain Name System (DNS) Database
RFC 3404	Dynamic Delegation Discovery System (DDDS) Part Four: The Uniform Resource Identifiers (URI) Resolution Application
RFC 3405	Dynamic Delegation Discovery System (DDDS) Part Five: URI.ARPA Assignment Procedures
RFC 3492	Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDNA)	March 2003	Punycode
RFC 3501	INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1	March 2003	IMAP v 4r1
RFC 3530	Network File System (NFS) version 4 Protocol	April 2003	NFS v 4
RFC 3538	Secure Electronic Transaction (SET) Supplement for the v1.0 Internet Open Trading Protocol (IOTP)	June 2003	Internet Open Trading Protocol
RFC 3550	RTP: A Transport Protocol for Real-Time Applications	July 2003	RTP
RFC 3711	The Secure Real-time Transport Protocol (SRTP)	March 2004	SRTP
RFC 3720	Internet Small Computer Systems Interface (iSCSI)	April 2004	ISCSI
RFC 3730	Extensible Provisioning Protocol (EPP)	March 2004	Extensible Provisioning Protocol
RFC 3783	Small Computer Systems Interface (SCSI) Command Ordering Considerations with iSCSI	May 2004	ISCSI
RFC 3801	Voice Profile for Internet Protocol	June 2004	VPIM
RFC 3830	MIKEY: Multimedia Internet KEYing	August 2004	MIKEY
RFC 3867	Payment Application Programmers Interface (API) for v1.0	November 2004	Internet Open Trading Protocol
RFC 3977	Network News Transfer Protocol	October 2006	NNTP
RFC 4121	The Kerberos Version 5 - Generic Security Service Application Program Interface (GSS-API)	July 2005	Kerberos
RFC 4122	A Universally Unique IDentifier (UUID) URN Namespace	July 2005	UUID
RFC 4151	The 'tag' URI Scheme	October 2005	Tag URI scheme
RFC 4213	Basic Transition Mechanisms for IPv6 Hosts and Routers	October 2005	6in4
RFC 4217	Securing FTP with TLS	October 2005	SSL FTP (FTPS)
RFC 4271	Border Gateway Protocol 4	January 2006	Border Gateway Protocol
RFC 4287	The Atom Syndication Format	December 2005	Atom
RFC 4251	The Secure Shell (SSH) Protocol Architecture	January 2006	SSH-2
RFC 4291	IP Version 6 Addressing Architecture	February 2006	IPv6
RFC 4353	A Framework for Conferencing with the Session Initiation Protocol (SIP)	February 2006	Conference call
RFC 4408	Sender Policy Framework (SPF) for Authorizing Use of Domains in E-Mail, Version 1	January 2006	SPF
RFC 4422	Simple Authentication and Security Layer (SASL)	June 2006	SASL
RFC 4541	Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Snooping Switches	May 2006	IGMP snooping
RFC 4575	A Session Initiation Protocol (SIP) Event Package for Conference State	August 2006	Conference call
RFC 4579	Session Initiation Protocol (SIP) Call Control - Conferencing for User Agents	August 2006
RFC 4634	US Secure Hash Algorithms (SHA and HMAC-SHA)	July 2006	SHA-1, SHA-2
RFC 4655	A Path Computation Element (PCE)-Based Architecture	August 2008	Path computation element
RFC 4787	Network Address Translation (NAT) Behavioral Requirements for Unicast UDP	January 2007	NAT
RFC 4960	Stream Control Transmission Protocol	September 2007	SCTP
RFC 5023	The Atom Publishing Protocol	October 2007	Atom
RFC 5228	Sieve: An Email Filtering Language	January 2008	Sieve		Obsoletes RFC 3028
RFC 5321	Simple Mail Transfer Protocol	October 2008	SMTP, Internet Message Format
RFC 5322	Internet Message Format	October 2008
RFC 5533	Shim6: Level 3 Multihoming Shim Protocol for IPv6	June 2009	Site Multihoming by IPv6 Intermediation
RFC 5545	iCalendar Specification	September 2009	iCalendar
RFC 5646	Tags for Identifying Languages	September 2009	language tags
RFC 5849	The OAuth 1.0 Protocol	April 2010	OAuth
RFC 5880	Bidirectional Forwarding Detection	June 2010	BFD
RFC 5881	BFD for IPv4 and IPv6 (Single Hop)	June 2010	BFD
RFC 5905	Network Time Protocol Version 4: Protocol and Algorithms Specification	June 2010	NTP v 4		Obsoletes RFC 1305, RFC 4330
RFC 5969	IPv6 Rapid Deployment on IPv4 Infrastructures (6rd)	January 2010	IPv6 rapid deployment
RFC 6238	TOTP: Time-Based One-Time Password Algorithm	May 2011	TOTP
RFC 6265	HTTP State Management Mechanism	April 2011	HTTP cookie
RFC 6409	Message submission for mail	November 2011	message submission agent		replaces 2476, 4409
RFC 6455	The WebSocket Protocol	December 2011	WebSocket
RFC 6508	Sakai-Kasahara Key Encryption (SAKKE)	February 2012	SAKKE
RFC 6716	Definition of the Opus Audio Codec	September 2012	Opus (audio format)		Updated by RFC 8251
RFC 6726	File Delivery over Unidirectional Transport (FLUTE)	November 2012	FLUTE		Obsoletes RFC 3926
RFC 6749	The OAuth 2.0 Authorization Framework	October 2012	OAuth
RFC 6797	HTTP Strict Transport Security (HSTS)	November 2012	HTTP Strict Transport Security
RFC 6805	The Application of the Path Computation Element Architecture to the Determination of a Sequence of Domains in MPLS and GMPLS	November 2012	Path computation element
RFC 7230	Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing	June 2014	HTTP v1.1		Obsoletes 2616
RFC 7231	Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content	June 2014	HTTP v1.1		Obsoletes 2616
RFC 7232	Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests	June 2014	HTTP v1.1		Obsoletes 2616
RFC 7233	Hypertext Transfer Protocol (HTTP/1.1): Range Requests	June 2014	HTTP v1.1, Byte serving		Obsoletes 2616
RFC 7234	Hypertext Transfer Protocol (HTTP/1.1): Caching	June 2014	HTTP v1.1		Obsoletes 2616
RFC 7235	Hypertext Transfer Protocol (HTTP/1.1): Authentication	June 2014	HTTP v1.1		Obsoletes 2616
RFC 7252	Constrained Application Protocol (CoAP)	June 2014	Constrained Application Protocol
RFC 7301	Transport Layer Security (TLS): Application-Layer Protocol Negotiation Extension	July 2014	Application-Layer Protocol Negotiation
RFC 7348	Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks	August 2014	VXLAN
RFC 7469	Public Key Pinning Extension for HTTP	April 2015	HTTP Public Key Pinning
RFC 7540	Hypertext Transfer Protocol Version 2 (HTTP/2)	May 2015	HTTP/2
RFC 7541	HPACK: Header Compression for HTTP/2	May 2015
RFC 7567	IETF Recommendations Regarding Active Queue Management	July 2015	Active Queue Management
RFC 7725	An HTTP Status Code to Report Legal Obstacles	December 2015	HTTP 451
RFC 7871	Client Subnet in DNS Queries	May 2016	Domain Name System
RFC 8391	XMSS: eXtended Merkle Signature Scheme	May 2018	Hash-based cryptography
RFC 8392	CBOR Web Token (CWT)	May 2018
RFC 9000	QUIC: A UDP-Based Multiplexed and Secure Transport	May 2021	QUIC
RFC 9293	Transmission Control Protocol (TCP)	August 2022	TCP		Obsoletes RFC 793
RFC 9338	CBOR Object Signing and Encryption (COSE): Countersignatures	December 2022	COSE		Updates RFC 9052
RFC 9580	OpenPGP	July 2024	OpenPGP		Obsoletes RFC 4880, RFC 5581, RFC 6637

Topical list

Obsolete RFCs are indicated with struck-through text.

Topic	Related RFCs
Address Resolution Protocol	RFC 826
Blocks Extensible Exchange Protocol	RFC 3080
Bidirectional Forwarding Detection	RFC 5880, RFC 5881
BOOTP	RFC 951
CRAM-MD5	RFC 2195
Date and Time on the Internet (ISO 8601)	RFC 3339
DEFLATE	RFC 1951
DISCARD	RFC 863
Domain Name System	RFC 1034, RFC 1035, RFC 2606, RFC 7871
Dynamic Delegation Discovery System	RFC 2168, RFC 2915, RFC 3401, RFC 3402, RFC 3403, RFC 3404, RFC 3405
Dynamic Host Configuration Protocol	RFC 1531, RFC 1541, RFC 2131, RFC 3315 (IPv6)
Extensible Messaging and Presence Protocol	RFC 3920 RFC 3921 RFC 3922
ECHO protocol	RFC 862
Fictitious domain name	RFC 2606
File Transfer Protocol	RFC 114, RFC 172, RFC 265, RFC 354, RFC 765, RFC 959, RFC 2228, RFC 4217
Frame Relay	RFC 1294, RFC 1490, RFC 2427
Generic Security Services Application Program Interface	RFC 1508, RFC 1509, RFC 1964, RFC 2078, RFC 2743, RFC 2744, RFC 2853
gzip	RFC 1952
HyperText Transfer Protocol	RFC 1945 (v 1.0), RFC 2616 (v 1.1), RFC 7230 (v 1.1), RFC 7231 (v 1.1), RFC 7232 (v 1.1), RFC 7233 (v 1.1), RFC 7234 (v 1.1), RFC 7235 (v 1.1)
Internet Control Message Protocol	RFC 792
Internet Group Management Protocol	RFC 966 (v 0), RFC 988 (v 0), RFC 1054 (v 1), 1112 (v 1), RFC 2236 (v 2), RFC 3376 (v 3)
Internet Key Exchange	IKE RFC 2409, RFC 2407 (ISAKMP), RFC 2408 (ISAKMP), IKEv2 RFC 4306, IKEv2 RFC 4301, RFC 4310 (DNS)
Internet Message Access Protocol	RFC 1176 (v 2), RFC 1730 (v 4), RFC 2060 (v 4r1), RFC 3501 (v 4r1)
Internet Protocol	see IPv4 and IPv6
IP over Avian Carriers	RFC 1149, RFC 2549
IPv4	RFC 760, RFC 790, RFC 791
IPv6	RFC 1883, RFC 2460, RFC 8200
IPv6 addressing	RFC 2373, RFC 3513, RFC 4291
Internet Relay Chat	RFC 1459, RFC 2810, RFC 2811, RFC 2812, RFC 2813
Internet Open Trading Protocol	RFC 2801, RFC 3504, RFC 2802, RFC 2935, RFC 3538, RFC 3867
ISCSI	RFC 3720, RFC 3783
Kerberos	RFC 1964
Lightweight Directory Access Protocol	RFC 1487, RFC 1777, RFC 2251, RFC 2252, RFC 2253, RFC 2254, RFC 2255, RFC 2256, RFC 4510, RFC 4511, RFC 4512, RFC 4513, RFC 4514, RFC 4515, RFC 4516, RFC 4517, RFC 4518, RFC 4519, RFC 4520, RFC 4521, RFC 4522, RFC 4523, RFC 4524, RFC 4525, RFC 4526, RFC 4527, RFC 4528, RFC 4529, RFC 4530, RFC 4531, RFC 4532, RFC 4533, RFC 4534
Microsoft Point-to-Point Encryption	RFC 2118, RFC 3078
MIKEY	RFC 3830, RFC 4650, RFC 4738, RFC 6043, RFC 6267, RFC 6509
MD5	RFC 1321
Multiprotocol Label Switching	RFC 3031
Multipurpose Internet Mail Extensions	RFC 2045 RFC 2046 RFC 2047 RFC 2049
Network address translation	RFC 1631, RFC 2663, RFC 2993, RFC 3022, RFC 3027, RFC 3234, RFC 3489, RFC 4787, RFC 5389
Network File System	RFC 1094, RFC 1813 (v.3), RFC 3010 (v.4), RFC 3530 (v.4)
Network News Transfer Protocol	RFC 977, RFC 3977
Network Time Protocol	RFC 1059 (v.1), RFC 1119 (v.2), RFC 1305 (v.3), RFC 5905 (v.4)
Open Shortest Path First	RFC 1131 (v.1), RFC 1247 (v.2), RFC 1583 (v.2), RFC 2178 (v.2), RFC 2328, RFC 2740 (IPv6), RFC 5340 (IPv6)
Pretty Good Privacy	RFC 1991, RFC 2440, RFC 4880
Protocol Independent Multicast	RFC 2117, RFC 2362 (SM), RFC 4602 (SM)
Reverse Address Resolution Protocol	RFC 903
QUIC	RFC 9000
Post Office Protocol	RFC 918 (v.1), RFC 937 (v.2), RFC 1081 (v.3), RFC 1225 (v.3), RFC 1460 (v.3), RFC 1725 (v.3), RFC 1939 (v.3)
RADIUS	RFC 2058, RFC 2059, RFC 2138, RFC 2139, RFC 2865, RFC 2866, RFC 2867, RFC 2868, RFC 2869, RFC 3162 (IPv6)
Real-time Transport Protocol	RFC 1889
Real Time Streaming Protocol	RFC 2326
Routing Information Protocol	RFC 1058 (v.1), RFC 1388 (v.2), RFC 1723 (v.2), RFC 2453 (v.2), RFC 2080 (v.ng)
Sender Policy Framework	RFC 4408
Secure Shell-2	RFC 4251
Session Announcement Protocol	RFC 2974
Session Description Protocol	RFC 2327
Session Initiation Protocol	RFC 3261
SHA hash functions	RFC 3174, RFC 4634
Simple Authentication and Security Layer	RFC 2222, RFC 4422
Simple Mail Transfer Protocol, Internet Message Format	RFC 196, RFC 772, RFC 821, RFC 822, RFC 2821, RFC 2822, RFC 5321, RFC 5322
Simple Network Management Protocol	RFC 1067, RFC 1098, RFC 1157 (v.1), RFC 1441 (v.2) RFC 2570 (v.3)
Stream Control Transmission Protocol	RFC 2960, RFC 4960, RFC 3286
Tag URI scheme	RFC 4151
TELNET	RFC 15, RFC 854, RFC 855
Transmission Control Protocol	RFC 675, RFC 793, RFC 9293
Transport Layer Security 1.0	RFC 2246
Trivial File Transfer Protocol	RFC 783, RFC 1350
Usenet	RFC 850, RFC 1036
Uniform Resource Identifier	RFC 3986
User Datagram Protocol	RFC 768
UTF-8	RFC 3629
zlib	RFC 1950

External links

• RFC-Editor - Document Retrieval - search engine
• RFC Database - contains various lists of RFCs
• RFC Bibliographic Listing - Listing of bibliographic entries for all RFCs. Also notes when an RFC has been made obsolete.