35:(a TCP option), which is a cryptographic cookie stored on the client and set upon the initial connection with the server. When the client later reconnects, it sends the initial SYN packet along with the TFO cookie data to authenticate itself. If successful, the server may start sending data to the client even before the reception of the final ACK packet of the three-way handshake, thus skipping a round-trip delay and lowering the
50:
that is difficult for third parties to spoof, even if they can forge a source IP address or make two-way connections to the same server from other IP addresses. Although it uses cryptographic techniques to generate the cookie, TFO is not intended to provide more security than the three-way handshake
85:
The TFO proposal was originally presented in 2011 and was published as the experimental RFC 7413 in
December 2014. TCP Fast Open shares the goal of bypassing the three-way handshake of TCP with an earlier proposal from 1994, called
51:
it replaces, and does not give any form of cryptographic protection to the resulting TCP connection, or provide identity assurance about either endpoint. It also is not intended to be resistant to
109:
in kernel versions 3.6 (support for clients) and 3.7 (Dec 2012) (support for servers), and was turned on by default in kernel version 3.13 (Jan 2014). TFO support for
90:(RFC 1644). In contrast to TCP Fast Open, T/TCP paid no attention to security, opening a path for vulnerabilities and failing to gain traction.
663:
337:
28:
627:
441:
415:
148:
77:
challenges; the TFO cookie can allow persistently tracking a client across sessions, even by passive observers.
126:
56:
52:
565:
125:
from version 58. The support was disabled by default due to network device compatibility issues with TFO and
758:
237:
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136:
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106:
36:
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55:. If such resistance is required, it may be used in combination with a cryptographic protocol such as
351:
163:
495:
481:
467:
310:
157:
708:
172:
47:
468:"Implementation of server-side TCP Fast Open (TFO) [RFC7413]: MFC into stable/10 branch"
738:
718:
341:
74:
695:
Sy, Erik; Mueller, Tobias; Burkert, Christian; Federrath, Hannes; Fischer, Mathias (2020).
330:
Cheng, Yuchung; Chu, Jerry; Radhakrishnan, Sivasankar & Jain, Arvind (December 2014).
122:
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both support TCP Fast Open, but it is not enabled for individual connections by default.
648:
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482:"This is an implementation of the client side of TCP Fast Open (TFO) [RFC7413]"
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132:
43:
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331:
232:
67:
202:
192:
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723:
696:
442:"Linux Kernel 3.16, Section 1.4. TCP Fast Open server mode on IPv6 support"
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TFO has been difficult to deploy due to protocol ossification; in 2020, no
208:
178:
144:
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from version 10.3 (support for servers) and 12.0. (support for clients).
46:
keyed on a key held secret by the server to the client's, generating an
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271:
214:
116:
346:
713:
681:
416:"Linux Kernel 3.13, Section 1.10. TCP Fast Open enabled by default"
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267:
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Radhakrishnan S, Cheng Y, Chu J, Jain A, Raghavan B (2011-12-06).
242:
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140:
87:
60:
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169:
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110:
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31:(TCP) connections between two endpoints. It works by using a
697:"Enhanced Performance and Privacy for TLS over TCP Fast Open"
664:"Support TCP fastopen on incoming and outgoing connections"
403:
Linux 3.7. TCP Fast Open will now be supported on servers
296:
27:) is an extension to speed up the opening of successive
381:
The client-side support has been merged for Linux 3.6
628:"Windows 10 build 14352 - New web platform features"
217:
supports TCP-fastopen (RFC-7413) from version 2.81.
496:"Enable TCP_FASTOPEN by default for FreeBSD 12"
701:Proceedings on Privacy Enhancing Technologies
8:
395:"Linux 3.7 arrives, ARM developers rejoice"
98:TFO implementations include the following:
284:
113:servers was merged in kernel version 3.16.
722:
712:
345:
524:"1398201 - Disable TCP Fast Open for 57"
393:Vaughan-Nichols, Steven J (2012-12-11).
377:"TCP Fast Open: expediting web services"
268:"TCP Fast Open: expediting web services"
211:supports TCP Fast Open from version 4.1.
614:"Your App and Next Generation Networks"
586:"Release Notes for BIND Version 9.11.0"
258:
42:The cookie is generated by applying a
129:and eventually removed in version 87.
7:
325:
323:
105:support for TFO was merged into the
680:Rybczyńska, Marta (13 March 2020).
39:in the start of data transmission.
14:
510:"1188435 - Support TCP Fast Open"
139:browsers have support for TFO on
538:"1689604 - Remove TCP FastOpen"
375:Kerrisk, Michael (2012-08-01).
266:Kerrisk, Michael (2012-08-01).
1:
201:supports TCP Fast Open since
29:Transmission Control Protocol
662:Kelley, Simon (2019-03-10).
775:
175:(DNS) from version 9.11.0.
16:Experimental TCP mechanism
53:man-in-the-middle attacks
724:10.2478/popets-2020-0027
160:(MTA) from version 4.88.
19:In computer networking,
682:"A QUIC look at HTTP/3"
651:. PowerDNS. 2017-12-04.
238:TCP Cookie Transactions
649:"Changelogs for 4.1.x"
399:Linux and Open Source
107:Linux kernel mainline
552:"Exim 4.88 released"
205:Preview build 14352.
166:from version 1.5.10.
164:Unbound DNS Resolver
70:used it by default.
181:from version 2.6.0.
158:mail transfer agent
616:. Apple Inc. 2015.
299:, p. 275-279.
173:Domain Name System
48:authentication tag
446:kernelnewbies.org
422:. 19 January 2014
420:kernelnewbies.org
209:PowerDNS Recursor
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123:Mozilla Firefox
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94:Characteristics
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733:External links
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707:(2): 271–287.
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602:. 2017-09-29.
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588:. 2016-10-05.
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554:. 2016-12-25.
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540:. 2021-03-23.
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526:. 2017-09-10.
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512:. 2017-05-05.
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498:. 2018-06-24.
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470:. 2015-12-28.
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333:TCP Fast Open
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316:. ACM CoNEXT.
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21:TCP Fast Open
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632:. Retrieved
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569:. Retrieved
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452:14 September
450:. Retrieved
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424:. Retrieved
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358:. Retrieved
332:
304:
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261:
143:, including
97:
84:
72:
68:Web browsers
65:
44:block cipher
41:
32:
24:
20:
18:
630:. Microsoft
426:11 February
379:. LWN.net.
233:SYN cookies
714:1905.03518
634:2016-05-27
571:2017-12-05
254:References
203:Windows 10
193:OS X 10.11
33:TFO cookie
401:. ZDNet.
753:Category
222:See also
179:Knot DNS
145:ChromeOS
137:Chromium
687:LWN.net
360:27 June
272:LWN.net
215:dnsmasq
149:Android
127:TLS 1.3
117:FreeBSD
81:History
75:privacy
37:latency
741:
709:arXiv
314:(PDF)
243:0-RTT
189:iOS 9
185:Apple
141:Linux
88:T/TCP
61:IPsec
743:7413
705:2020
454:2014
428:2014
362:2022
355:7413
338:IETF
248:QUIC
228:SPDY
191:and
170:BIND
155:Exim
147:and
135:and
111:IPv6
103:IPv4
739:RFC
719:doi
352:RFC
342:doi
187:'s
59:or
57:TLS
25:TFO
755::
717:.
703:.
699:.
684:.
444:.
418:.
397:.
350:.
340:.
336:.
322:^
270:.
63:.
727:.
721::
711::
690:.
666:.
637:.
574:.
456:.
430:.
364:.
344::
287:.
274:.
151:.
23:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.