Telnet Options (original) (raw)

Last Updated

2022-03-16

Available Formats

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Registries Included Below

Telnet Options

Registration Procedure(s)

IETF Review

Reference

[RFC855]

Note

The Telnet Protocol has a number of options that may be negotiated. These options are listed here. "Internet Official Protocol Standards" (STD 1) provides more detailed information.

Available Formats

CSV

Options Name Reference
0 Binary Transmission [RFC856]
1 Echo [RFC857]
2 Reconnection [NIC 15391 of 1973]
3 Suppress Go Ahead [RFC858]
4 Approx Message Size Negotiation [NIC 15393 of 1973]
5 Status [RFC859]
6 Timing Mark [RFC860]
7 Remote Controlled Trans and Echo [RFC726]
8 Output Line Width [NIC 20196 of August 1978]
9 Output Page Size [NIC 20197 of August 1978]
10 Output Carriage-Return Disposition [RFC652]
11 Output Horizontal Tab Stops [RFC653]
12 Output Horizontal Tab Disposition [RFC654]
13 Output Formfeed Disposition [RFC655]
14 Output Vertical Tabstops [RFC656]
15 Output Vertical Tab Disposition [RFC657]
16 Output Linefeed Disposition [RFC658]
17 Extended ASCII [RFC698]
18 Logout [RFC727]
19 Byte Macro [RFC735]
20 Data Entry Terminal [RFC1043][RFC732]
21 SUPDUP [RFC736][RFC734]
22 SUPDUP Output [RFC749]
23 Send Location [RFC779]
24 Terminal Type [RFC1091]
25 End of Record [RFC885]
26 TACACS User Identification [RFC927]
27 Output Marking [RFC933]
28 Terminal Location Number [RFC946]
29 Telnet 3270 Regime [RFC1041]
30 X.3 PAD [RFC1053]
31 Negotiate About Window Size [RFC1073]
32 Terminal Speed [RFC1079]
33 Remote Flow Control [RFC1372]
34 Linemode [RFC1184]
35 X Display Location [RFC1096]
36 Environment Option [RFC1408]
37 Authentication Option [RFC2941]
38 Encryption Option [RFC2946]
39 New Environment Option [RFC1572]
40 TN3270E [RFC2355]
41 XAUTH [Rob_Earhart]
42 CHARSET [RFC2066]
43 Telnet Remote Serial Port (RSP) [Robert_Barnes]
44 Com Port Control Option [RFC2217]
45 Telnet Suppress Local Echo [Wirt_Atmar]
46 Telnet Start TLS [Michael_Boe]
47 KERMIT [RFC2840]
48 SEND-URL [David_Croft]
49 FORWARD_X [Jeffrey_Altman]
50-137 Unassigned [IANA]
138 TELOPT PRAGMA LOGON [Steve_McGregory]
139 TELOPT SSPI LOGON [Steve_McGregory]
140 TELOPT PRAGMA HEARTBEAT [Steve_McGregory]
141-254 Unassigned
255 Extended-Options-List [RFC861]

Telnet Authentication Types (Option 37)

Registration Procedure(s)

First Come First Served

Reference

[RFC2941]

KERBEROS_V4 Telnet Authentication Type (Type 1)

Registration Procedure(s)

First Come First Served

Reference

[RFC1411]

Available Formats

CSV

Suboption Command Reference
0 AUTH [RFC1411]
1 REJECT [RFC1411]
2 ACCEPT [RFC1411]
3 CHALLENGE [RFC1411]
4 RESPONSE [RFC1411]
5 FORWARD [Derrick_Brashear]
6 FORWARD-ACCEPT [Derrick_Brashear]
7 FORWARD-REJECT [Derrick_Brashear]
8 EXP [Thomas_Wu]
9 PARAMS [Thomas_Wu]

KERBEROS_V5 Telnet Authentication Type (Type 2)

Registration Procedure(s)

Specification Required

Expert(s)

Unassigned

Reference

[RFC2942]

Available Formats

CSV

Suboption Command Reference
0 AUTH [RFC2942]
1 REJECT [RFC2942]
2 ACCEPT [RFC2942]
3 RESPONSE [RFC2942]
4 FORWARD [RFC2942]
5 FORWARD_ACCEPT [RFC2942]
6 FORWARD-REJECT [RFC2942]

SRP Telnet Authentication Type (Type 5)

Registration Procedure(s)

Specification Required

Expert(s)

Unassigned

Reference

[RFC2944]

Available Formats

CSV

Suboption Command Reference
0 AUTH [RFC2944]
1 REJECT [RFC2944]
2 ACCEPT [RFC2944]
3 CHALLENGE [RFC2944]
4 RESPONSE [RFC2944]
5-7 Unassigned [RFC2944]
8 EXP [RFC2944]
9 PARAMS [RFC2944]

KEA_SJ (Type 12) and KEA_SJ_INTEG (Type 13) Authentication Types

Registration Procedure(s)

Specification Required

Expert(s)

Unassigned

Reference

[RFC2951]

Available Formats

CSV

Suboption Command Reference
1 KEA_CERTA_RA [RFC2951]
2 KEA_CERTB_RB_IVB_NONCEB [RFC2951]
3 KEA_IVA_RESPONSEB_NONCEA [RFC2951]
4 KEA_RESPONSEA [RFC2951]

DSS Authentication Type (Type 14)

Registration Procedure(s)

Specification Required

Expert(s)

Unassigned

Reference

[RFC2943]

Available Formats

CSV

Suboption Command Reference
1 DSS_INITIALIZE [RFC2943]
2 DSS_TOKENBA [RFC2943]
3 DSS_CERTA_TOKENAB [RFC2943]
4 DSS_CERTB_TOKENBA2 [RFC2943]

Telnet Encryption Types (Option 38)

Registration Procedure(s)

First Come First Served

Reference

[RFC2946]

Note

In the Telnet Encryption commands and types [RFC2946] there have been various implementations in several widely distributed versions of Telnet (e.g., at MIT, Stanford, and Columbia). Originally, only two encryption types were specified. Additional encryption types have been defined and are listed below. Additions to the list are registered by the IANA and documented here.

DES_CFB64 Telnet Encryption Type (Type 1)

Registration Procedure(s)

First Come First Served

Reference

[RFC2952]

Available Formats

CSV

Suboption Command Reference
1 CFB64_IV [RFC2952]
2 CFB64_IV_OK [RFC2952]
3 CFB64_IV_BAD [RFC2952]

DES_OFB64 Telnet Encryption Type (Type 2)

Registration Procedure(s)

First Come First Served

Reference

[RFC2953]

Available Formats

CSV

Suboption Command Reference
1 OFB64_IV [RFC2953]
2 OFB64_IV_OK [RFC2953]
3 OFB64_IV_BAD [RFC2953]

DES3_CFB64 Telnet Encryption Type (Type 3)

Registration Procedure(s)

First Come First Served

Reference

[RFC2947]

Available Formats

CSV

Suboption Command Reference
1 CFB64_IV [RFC2947]
2 CFB64_IV_OK [RFC2947]
3 CFB64_IV_BAD [RFC2947]

DES3_OFB64 Telnet Encryption Type (Type 4)

Registration Procedure(s)

First Come First Served

Reference

[RFC2948]

Available Formats

CSV

Suboption Command Reference
1 OFB64_IV [RFC2948]
2 OFB64_IV_OK [RFC2948]
3 OFB64_IV_BAD [RFC2948]

CAST5_40_CFB64 (Type 8) and CAST128_CFB64 (Type 10) Telnet Encryption Types

Registration Procedure(s)

First Come First Served

Reference

[RFC2950]

Available Formats

CSV

Suboption Command Reference
1 CFB64_IV [RFC2950]
2 CFB64_IV_OK [RFC2950]
3 CFB64_IV_BAD [RFC2950]

CAST5_40_OFB64 (Type 9) and CAST128_OFB64 (Type 11) Telnet Encryption Types

Registration Procedure(s)

First Come First Served

Reference

[RFC2949]

Available Formats

CSV

Suboption Command Reference
1 OFB64_IV [RFC2949]
2 OFB64_IV_OK [RFC2949]
3 OFB64_IV_BAD [RFC2949]

Contact Information

ID Name Contact URI Last Updated
[David_Croft] David Croft mailto:david&infotrek.co.uk 1998-09
[Derrick_Brashear] Derrick Brashear mailto:shadow&dementia.org 1995-01
[IANA] Internet Assigned Numbers Authority mailto:iana&iana.org 2012-08
[Jeffrey_Altman] Jeffrey Altman mailto:jaltman&watsun.cc.columbia.edu 2000-01
[Louis_Kahn] Louis Kahn mailto:louisk&microsoft.com 1998-10
[Michael_Boe] Michael Boe mailto:mboe&cisco.com 1998-06
[Rob_Earhart] Rob Earhart mailto:earhart+&cmu.edu 1995-04
[Robert_Barnes] Robert Barnes mailto:rab&stallion.oz.au 1997-07
[S_Josefsson] S. Josefsson mailto:jas&extundo.com http://josefsson.org/shishi/shishi.html#Telnet%20encryption%20with%20AES-CCM 2003-11
[Steve_McGregory] Steve McGregory mailto:stevemc&pragmasys.com 1998-12
[Steven_Schoch] Steven Schoch mailto:schoch&sheba.arc.nasa.gov 1995-01
[Thomas_Wu] Thomas Wu mailto:tjw&stanford.edu 1998-09
[Wirt_Atmar] Wirt Atmar mailto:atmar&aics-research.com 1998-06

Footnote

[1] Authentication types never submitted to the IETF for consideration as an Internet standard.