1.\" $NetBSD: telnet.1,v 1.25 2002/09/30 11:09:13 grant Exp $ 2.\" 3.\" Copyright (c) 1983, 1990, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" from: @(#)telnet.1 8.4 (Berkeley) 2/3/94 35.\" 36.Dd February 3, 1994 37.Dt TELNET 1 38.Os 39.Sh NAME 40.Nm telnet 41.Nd user interface to the 42.Tn TELNET 43protocol 44.Sh SYNOPSIS 45.Nm "" 46.Op Fl 4 47.Op Fl 6 48.Op Fl 8 49.Op Fl E 50.Op Fl F 51.Op Fl K 52.Op Fl L 53.Op Fl N 54.Bk -words 55.Op Fl S Ar tos 56.Ek 57.Bk -words 58.Op Fl X Ar authtype 59.Ek 60.Op Fl a 61.Op Fl c 62.Op Fl d 63.Bk -words 64.Op Fl e Ar escapechar 65.Ek 66.Op Fl f 67.Bk -words 68.Op Fl k Ar realm 69.Ek 70.Bk -words 71.Op Fl l Ar user 72.Ek 73.Bk -words 74.Op Fl n Ar tracefile 75.Ek 76.Bk -words 77.Op Fl P Ar policy 78.Ek 79.Op Fl r 80.Op Fl x 81.Oo 82.Ar host 83.Op Ar port 84.Oc 85.Sh DESCRIPTION 86The 87.Nm 88command 89is used to communicate with another host using the 90.Tn TELNET 91protocol. 92If 93.Nm 94is invoked without the 95.Ar host 96argument, it enters command mode, 97indicated by its prompt 98.Pq Nm telnet\&\*[Gt] . 99In this mode, it accepts and executes the commands listed below. 100If it is invoked with arguments, it performs an 101.Ic open 102command with those arguments. 103.Pp 104Options: 105.Bl -tag -width indent 106.It Fl 4 107Forces 108.Nm 109to use IPv4 addresses only. 110.It Fl 6 111Forces 112.Nm 113to use IPv6 addresses only. 114.It Fl 8 115Specifies an 8-bit data path. 116This causes an attempt to 117negotiate the 118.Dv TELNET BINARY 119option on both input and output. 120.It Fl E 121Stops any character from being recognized as an escape character. 122.It Fl F 123If Kerberos V5 authentication is being used, the 124.Fl F 125option allows the local credentials to be forwarded 126to the remote system, including any credentials that 127have already been forwarded into the local environment. 128.It Fl K 129Specifies no automatic login to the remote system. 130.It Fl L 131Specifies an 8-bit data path on output. 132This causes the 133BINARY option to be negotiated on output. 134.It Fl N 135Numeric host address. 136No attempt will be made to look up 137symbolic names for host addresses. 138.It Fl S Ar tos 139Sets the IP type-of-service (TOS) option for the telnet 140connection to the value 141.Ar tos , 142which can be a numeric TOS value 143or, on systems that support it, a symbolic 144TOS name found in the /etc/iptos file. 145.It Fl X Ar atype 146Disables the 147.Ar atype 148type of authentication. 149.It Fl a 150Attempt automatic login. 151Currently, this sends the user name via the 152.Ev USER 153variable 154of the 155.Ev ENVIRON 156option if supported by the remote system. 157The name used is that of the current user as returned by 158.Xr getlogin 2 159if it agrees with the current user ID, 160otherwise it is the name associated with the user ID. 161.It Fl c 162Disables the reading of the user's 163.Pa \&.telnetrc 164file. 165(See the 166.Ic toggle skiprc 167command on this man page.) 168.It Fl d 169Sets the initial value of the 170.Ic debug 171toggle to 172.Dv TRUE . 173.It Fl e Ar escape char 174Sets the initial 175.Nm 176escape character to 177.Ar escape char . 178If 179.Ar escape char 180is omitted, then 181there will be no escape character. 182.It Fl f 183If Kerberos V5 authentication is being used, the 184.Fl f 185option allows the local credentials to be forwarded to the remote system. 186.It Fl k Ar realm 187If Kerberos authentication is being used, the 188.Fl k 189option requests that telnet obtain tickets for the remote host in 190realm 191.Ar realm 192instead of the remote host's realm, as determined by 193.Xr krb_realmofhost 3 . 194.It Fl l Ar user 195When connecting to the remote system, if the remote system 196understands the 197.Ev ENVIRON 198option, then 199.Ar user 200will be sent to the remote system as the value for the variable USER. 201This option implies the 202.Fl a 203option. 204This option may also be used with the 205.Ic open 206command. 207.It Fl n Ar tracefile 208Opens 209.Ar tracefile 210for recording trace information. 211See the 212.Ic set tracefile 213command below. 214.It Fl P Ar policy 215Use IPsec policy specification string 216.Ar policy , 217for the connections. 218See 219.Xr ipsec_set_policy 3 220for details. 221.It Fl r 222Specifies a user interface similar to 223.Xr rlogin 1 . 224In this 225mode, the escape character is set to the tilde (~) character, 226unless modified by the 227.Fl e 228option. 229.It Fl x 230Turns on encryption of the data stream if possible. 231This 232option is not available outside of the United States and 233Canada. 234.It Ar host 235Indicates the official name, an alias, or the Internet address 236of a remote host. 237.It Ar port 238Indicates a port number (address of an application). 239If a number is 240not specified, the default 241.Nm 242port is used. 243.El 244.Pp 245When in rlogin mode, a line of the form ~. 246disconnects from the 247remote host; ~ is the telnet escape character. 248Similarly, the line ~^Z suspends the telnet session. 249The line ~^] escapes to the normal telnet escape prompt. 250.Pp 251Once a connection has been opened, 252.Nm 253will attempt to enable the 254.Dv TELNET LINEMODE 255option. 256If this fails, then 257.Nm 258will revert to one of two input modes: 259either \*(Lqcharacter at a time\*(Rq 260or \*(Lqold line by line\*(Rq 261depending on what the remote system supports. 262.Pp 263When 264.Dv LINEMODE 265is enabled, character processing is done on the 266local system, under the control of the remote system. 267When input 268editing or character echoing is to be disabled, the remote system 269will relay that information. 270The remote system will also relay 271changes to any special characters that happen on the remote 272system, so that they can take effect on the local system. 273.Pp 274In \*(Lqcharacter at a time\*(Rq mode, most 275text typed is immediately sent to the remote host for processing. 276.Pp 277In \*(Lqold line by line\*(Rq mode, all text is echoed locally, 278and (normally) only completed lines are sent to the remote host. 279The \*(Lqlocal echo character\*(Rq (initially \*(Lq^E\*(Rq) may be used 280to turn off and on the local echo 281(this would mostly be used to enter passwords 282without the password being echoed). 283.Pp 284If the 285.Dv LINEMODE 286option is enabled, or if the 287.Ic localchars 288toggle is 289.Dv TRUE 290(the default for \*(Lqold line by line\*(Lq; see below), 291the user's 292.Ic quit , 293.Ic intr , 294and 295.Ic flush 296characters are trapped locally, and sent as 297.Tn TELNET 298protocol sequences to the remote side. 299If 300.Dv LINEMODE 301has ever been enabled, then the user's 302.Ic susp 303and 304.Ic eof 305are also sent as 306.Tn TELNET 307protocol sequences, 308and 309.Ic quit 310is sent as a 311.Dv TELNET ABORT 312instead of 313.Dv BREAK . 314There are options (see 315.Ic toggle 316.Ic autoflush 317and 318.Ic toggle 319.Ic autosynch 320below) 321which cause this action to flush subsequent output to the terminal 322(until the remote host acknowledges the 323.Tn TELNET 324sequence) and flush previous terminal input 325(in the case of 326.Ic quit 327and 328.Ic intr ) . 329.Pp 330While connected to a remote host, 331.Nm 332command mode may be entered by typing the 333.Nm 334\*(Lqescape character\*(Rq (initially \*(Lq^]\*(Rq). 335When in command mode, the normal terminal editing conventions are available. 336.Pp 337The following 338.Nm 339commands are available. 340Only enough of each command to uniquely identify it need be typed 341(this is also true for arguments to the 342.Ic mode , 343.Ic set , 344.Ic toggle , 345.Ic unset , 346.Ic slc , 347.Ic environ , 348and 349.Ic display 350commands). 351.Pp 352.Bl -tag -width "mode type" 353.It Ic auth Ar argument ... 354The auth command manipulates the information sent through the 355.Dv TELNET AUTHENTICATE 356option. 357Valid arguments for the 358auth command are as follows: 359.Bl -tag -width "disable type" 360.It Ic disable Ar type 361Disables the specified type of authentication. 362To obtain a list of available types, use the 363.Ic auth disable \&? 364command. 365.It Ic enable Ar type 366Enables the specified type of authentication. 367To obtain a list of available types, use the 368.Ic auth enable \&? 369command. 370.It Ic status 371Lists the current status of the various types of 372authentication. 373.El 374.It Ic close 375Close a 376.Tn TELNET 377session and return to command mode. 378.It Ic display Ar argument ... 379Displays all, or some, of the 380.Ic set 381and 382.Ic toggle 383values (see below). 384.It Ic encrypt Ar argument ... 385The encrypt command manipulates the information sent through the 386.Dv TELNET ENCRYPT 387option. 388.Pp 389Note: Because of export controls, the 390.Dv TELNET ENCRYPT 391option is not supported outside of the United States and Canada. 392.Pp 393Valid arguments for the encrypt command are: 394.Bl -tag -width Ar 395.It Ic disable Ar type Ic [input|output] 396Disables the specified type of encryption. 397If you omit the input and output, both input and output 398are disabled. 399To obtain a list of available types, use the 400.Ic encrypt disable \&? 401command. 402.It Ic enable Ar type Ic [input|output] 403Enables the specified type of encryption. 404If you omit input and output, both input and output are 405enabled. 406To obtain a list of available types, use the 407.Ic encrypt enable \&? 408command. 409.It Ic input 410This is the same as the 411.Ic encrypt start input 412command. 413.It Ic -input 414This is the same as the 415.Ic encrypt stop input 416command. 417.It Ic output 418This is the same as the 419.Ic encrypt start output 420command. 421.It Ic -output 422This is the same as the 423.Ic encrypt stop output 424command. 425.It Ic start Ic [input|output] 426Attempts to start encryption. 427If you omit 428.Ic input 429and 430.Ic output , 431both input and output are enabled. 432To obtain a list of available types, use the 433.Ic encrypt enable \&? 434command. 435.It Ic status 436Lists the current status of encryption. 437.It Ic stop Ic [input|output] 438Stops encryption. 439If you omit input and output, 440encryption is on both input and output. 441.It Ic type Ar type 442Sets the default type of encryption to be used 443with later 444.Ic encrypt start 445or 446.Ic encrypt stop 447commands. 448.El 449.It Ic environ Ar arguments ... 450The 451.Ic environ 452command is used to manipulate the 453variables that may be sent through the 454.Dv TELNET ENVIRON 455option. 456The initial set of variables is taken from the users 457environment, with only the 458.Ev DISPLAY 459and 460.Ev PRINTER 461variables being exported by default. 462The 463.Ev USER 464variable is also exported if the 465.Fl a 466or 467.Fl l 468options are used. 469.Pp 470Valid arguments for the 471.Ic environ 472command are: 473.Bl -tag -width Fl 474.It Ic define Ar variable value 475Define the variable 476.Ar variable 477to have a value of 478.Ar value . 479Any variables defined by this command are automatically exported. 480The 481.Ar value 482may be enclosed in single or double quotes so 483that tabs and spaces may be included. 484.It Ic undefine Ar variable 485Remove 486.Ar variable 487from the list of environment variables. 488.It Ic export Ar variable 489Mark the variable 490.Ar variable 491to be exported to the remote side. 492.It Ic unexport Ar variable 493Mark the variable 494.Ar variable 495to not be exported unless 496explicitly asked for by the remote side. 497.It Ic list 498List the current set of environment variables. 499Those marked with a 500.Cm * 501will be sent automatically, 502other variables will only be sent if explicitly requested. 503.It Ic \&? 504Prints out help information for the 505.Ic environ 506command. 507.El 508.It Ic logout 509Sends the 510.Dv TELNET LOGOUT 511option to the remote side. 512This command is similar to a 513.Ic close 514command; however, if the remote side does not support the 515.Dv LOGOUT 516option, nothing happens. 517If, however, the remote side does support the 518.Dv LOGOUT 519option, this command should cause the remote side to close the 520.Tn TELNET 521connection. 522If the remote side also supports the concept of 523suspending a user's session for later reattachment, 524the logout argument indicates that you 525should terminate the session immediately. 526.It Ic mode Ar type 527.Ar Type 528is one of several options, depending on the state of the 529.Tn TELNET 530session. 531The remote host is asked for permission to go into the requested mode. 532If the remote host is capable of entering that mode, the requested 533mode will be entered. 534.Bl -tag -width Ar 535.It Ic character 536Disable the 537.Dv TELNET LINEMODE 538option, or, if the remote side does not understand the 539.Dv LINEMODE 540option, then enter \*(Lqcharacter at a time\*(Lq mode. 541.It Ic line 542Enable the 543.Dv TELNET LINEMODE 544option, or, if the remote side does not understand the 545.Dv LINEMODE 546option, then attempt to enter \*(Lqold-line-by-line\*(Lq mode. 547.It Ic isig Pq Ic \-isig 548Attempt to enable (disable) the 549.Dv TRAPSIG 550mode of the 551.Dv LINEMODE 552option. 553This requires that the 554.Dv LINEMODE 555option be enabled. 556.It Ic edit Pq Ic \-edit 557Attempt to enable (disable) the 558.Dv EDIT 559mode of the 560.Dv LINEMODE 561option. 562This requires that the 563.Dv LINEMODE 564option be enabled. 565.It Ic softtabs Pq Ic \-softtabs 566Attempt to enable (disable) the 567.Dv SOFT_TAB 568mode of the 569.Dv LINEMODE 570option. 571This requires that the 572.Dv LINEMODE 573option be enabled. 574.It Ic litecho Pq Ic \-litecho 575Attempt to enable (disable) the 576.Dv LIT_ECHO 577mode of the 578.Dv LINEMODE 579option. 580This requires that the 581.Dv LINEMODE 582option be enabled. 583.It Ic \&? 584Prints out help information for the 585.Ic mode 586command. 587.El 588.It Xo 589.Ic open Ar host 590.Op Fl l Ar user 591.Op Fl a 592.Oo Op \&- Ns 593.Ar port Oc 594.Xc 595Open a connection to the named host. 596If no port number 597is specified, 598.Nm 599will attempt to contact a 600.Tn TELNET 601server at the default port. 602The host specification may be either a host name (see 603.Xr hosts 5 ) 604or an Internet address specified in the \*(Lqdot notation\*(Rq (see 605.Xr inet 3 ) . 606The 607.Fl l 608option may be used to specify the user name 609to be passed to the remote system via the 610.Ev ENVIRON 611option. 612If a port is specified 613.Nm 614omits any automatic initialisation of 615.Tn TELNET 616options. 617When the port number is preceded by a minus sign, 618the initial option negotiation is done. 619After establishing a connection, the file 620.Pa \&.telnetrc 621in the 622user's home directory is opened. 623Lines beginning with a # are 624comment lines. 625Blank lines are ignored. 626Lines that begin 627without white space are the start of a machine entry. 628The 629first thing on the line is the name of the machine that is 630being connected to. 631The rest of the line, and successive 632lines that begin with white space are assumed to be 633.Nm 634commands and are processed as if they had been typed 635in manually to the 636.Nm 637command prompt. 638Commands associated with the special machine entry 639.Dv DEFAULT 640are processed for any given host. 641.It Ic quit 642Close any open 643.Tn TELNET 644session and exit 645.Nm "" . 646An end of file (in command mode) will also close a session and exit. 647.It Ic send Ar arguments 648Sends one or more special character sequences to the remote host. 649The following are the arguments which may be specified 650(more than one argument may be specified at a time): 651.Pp 652.Bl -tag -width escape 653.It Ic abort 654Sends the 655.Dv TELNET ABORT 656(Abort 657processes) 658sequence. 659.It Ic ao 660Sends the 661.Dv TELNET AO 662(Abort Output) sequence, which should cause the remote system to flush 663all output 664.Em from 665the remote system 666.Em to 667the user's terminal. 668.It Ic ayt 669Sends the 670.Dv TELNET AYT 671(Are You There) 672sequence, to which the remote system may or may not choose to respond. 673.It Ic brk 674Sends the 675.Dv TELNET BRK 676(Break) sequence, which may have significance to the remote 677system. 678.It Ic ec 679Sends the 680.Dv TELNET EC 681(Erase Character) 682sequence, which should cause the remote system to erase the last character 683entered. 684.It Ic el 685Sends the 686.Dv TELNET EL 687(Erase Line) 688sequence, which should cause the remote system to erase the line currently 689being entered. 690.It Ic eof 691Sends the 692.Dv TELNET EOF 693(End Of File) 694sequence. 695.It Ic eor 696Sends the 697.Dv TELNET EOR 698(End of Record) 699sequence. 700.It Ic escape 701Sends the current 702.Nm 703escape character (initially \*(Lq^\*(Rq). 704.It Ic ga 705Sends the 706.Dv TELNET GA 707(Go Ahead) 708sequence, which likely has no significance to the remote system. 709.It Ic getstatus 710If the remote side supports the 711.Dv TELNET STATUS 712command, 713.Ic getstatus 714will send the subnegotiation to request that the server send 715its current option status. 716.It Ic ip 717Sends the 718.Dv TELNET IP 719(Interrupt Process) sequence, which should cause the remote 720system to abort the currently running process. 721.It Ic nop 722Sends the 723.Dv TELNET NOP 724(No OPeration) 725sequence. 726.It Ic susp 727Sends the 728.Dv TELNET SUSP 729(SUSPend process) 730sequence. 731.It Ic synch 732Sends the 733.Dv TELNET SYNCH 734sequence. 735This sequence causes the remote system to discard all previously typed 736(but not yet read) input. 737This sequence is sent as 738.Tn TCP 739urgent 740data (and may not work if the remote system is a 741.Bx 4.2 742system -- if 743it doesn't work, a lower case \*(Lqr\*(Rq may be echoed on the terminal). 744.It Ic do Ar cmd 745.It Ic dont Ar cmd 746.It Ic will Ar cmd 747.It Ic wont Ar cmd 748Sends the 749.Dv TELNET DO 750.Ar cmd 751sequence. 752.Ar Cmd 753can be either a decimal number between 0 and 255, 754or a symbolic name for a specific 755.Dv TELNET 756command. 757.Ar Cmd 758can also be either 759.Ic help 760or 761.Ic \&? 762to print out help information, including 763a list of known symbolic names. 764.It Ic \&? 765Prints out help information for the 766.Ic send 767command. 768.El 769.It Ic set Ar argument value 770.It Ic unset Ar argument value 771The 772.Ic set 773command will set any one of a number of 774.Nm 775variables to a specific value or to 776.Dv TRUE . 777The special value 778.Ic off 779turns off the function associated with 780the variable, this is equivalent to using the 781.Ic unset 782command. 783The 784.Ic unset 785command will disable or set to 786.Dv FALSE 787any of the specified functions. 788The values of variables may be interrogated with the 789.Ic display 790command. 791The variables which may be set or unset, but not toggled, are 792listed here. 793In addition, any of the variables for the 794.Ic toggle 795command may be explicitly set or unset using 796the 797.Ic set 798and 799.Ic unset 800commands. 801.Bl -tag -width escape 802.It Ic ayt 803If 804.Tn TELNET 805is in localchars mode, or 806.Dv LINEMODE 807is enabled, and the status character is typed, a 808.Dv TELNET AYT 809sequence (see 810.Ic send ayt 811above) is sent to the 812remote host. 813The initial value for the "Are You There" 814character is the terminal's status character. 815.It Ic echo 816This is the value (initially \*(Lq^E\*(Rq) which, when in 817\*(Lqline by line\*(Rq mode, toggles between doing local echoing 818of entered characters (for normal processing), and suppressing 819echoing of entered characters (for entering, say, a password). 820.It Ic eof 821If 822.Nm 823is operating in 824.Dv LINEMODE 825or \*(Lqold line by line\*(Rq mode, entering this character 826as the first character on a line will cause this character to be 827sent to the remote system. 828The initial value of the eof character is taken to be the terminal's 829.Ic eof 830character. 831.It Ic erase 832If 833.Nm 834is in 835.Ic localchars 836mode (see 837.Ic toggle 838.Ic localchars 839below), 840.Sy and 841if 842.Nm 843is operating in \*(Lqcharacter at a time\*(Rq mode, then when this 844character is typed, a 845.Dv TELNET EC 846sequence (see 847.Ic send 848.Ic ec 849above) 850is sent to the remote system. 851The initial value for the erase character is taken to be 852the terminal's 853.Ic erase 854character. 855.It Ic escape 856This is the 857.Nm 858escape character (initially \*(Lq^[\*(Rq) which causes entry 859into 860.Nm 861command mode (when connected to a remote system). 862.It Ic flushoutput 863If 864.Nm 865is in 866.Ic localchars 867mode (see 868.Ic toggle 869.Ic localchars 870below) 871and the 872.Ic flushoutput 873character is typed, a 874.Dv TELNET AO 875sequence (see 876.Ic send 877.Ic ao 878above) 879is sent to the remote host. 880The initial value for the flush character is taken to be 881the terminal's 882.Ic flush 883character. 884.It Ic forw1 885.It Ic forw2 886If 887.Tn TELNET 888is operating in 889.Dv LINEMODE , 890these are the 891characters that, when typed, cause partial lines to be 892forwarded to the remote system. 893The initial value for 894the forwarding characters are taken from the terminal's 895eol and eol2 characters. 896.It Ic interrupt 897If 898.Nm 899is in 900.Ic localchars 901mode (see 902.Ic toggle 903.Ic localchars 904below) 905and the 906.Ic interrupt 907character is typed, a 908.Dv TELNET IP 909sequence (see 910.Ic send 911.Ic ip 912above) 913is sent to the remote host. 914The initial value for the interrupt character is taken to be 915the terminal's 916.Ic intr 917character. 918.It Ic kill 919If 920.Nm 921is in 922.Ic localchars 923mode (see 924.Ic toggle 925.Ic localchars 926below), 927.Ic and 928if 929.Nm 930is operating in \*(Lqcharacter at a time\*(Rq mode, then when this 931character is typed, a 932.Dv TELNET EL 933sequence (see 934.Ic send 935.Ic el 936above) 937is sent to the remote system. 938The initial value for the kill character is taken to be 939the terminal's 940.Ic kill 941character. 942.It Ic lnext 943If 944.Nm 945is operating in 946.Dv LINEMODE 947or \*(Lqold line by line\*(Lq mode, then this character is taken to 948be the terminal's 949.Ic lnext 950character. 951The initial value for the lnext character is taken to be 952the terminal's 953.Ic lnext 954character. 955.It Ic quit 956If 957.Nm 958is in 959.Ic localchars 960mode (see 961.Ic toggle 962.Ic localchars 963below) 964and the 965.Ic quit 966character is typed, a 967.Dv TELNET BRK 968sequence (see 969.Ic send 970.Ic brk 971above) 972is sent to the remote host. 973The initial value for the quit character is taken to be 974the terminal's 975.Ic quit 976character. 977.It Ic reprint 978If 979.Nm 980is operating in 981.Dv LINEMODE 982or \*(Lqold line by line\*(Lq mode, then this character is taken to 983be the terminal's 984.Ic reprint 985character. 986The initial value for the reprint character is taken to be 987the terminal's 988.Ic reprint 989character. 990.It Ic rlogin 991This is the rlogin escape character. 992If set, the normal 993.Tn TELNET 994escape character is ignored unless it is 995preceded by this character at the beginning of a line. 996This character, at the beginning of a line followed by 997a "." closes the connection; when followed by a ^Z it 998suspends the 999.Nm 1000command. 1001The initial state is to 1002disable the rlogin escape character. 1003.It Ic start 1004If the 1005.Dv TELNET TOGGLE-FLOW-CONTROL 1006option has been enabled, 1007then this character is taken to 1008be the terminal's 1009.Ic start 1010character. 1011The initial value for the start character is taken to be 1012the terminal's 1013.Ic start 1014character. 1015.It Ic stop 1016If the 1017.Dv TELNET TOGGLE-FLOW-CONTROL 1018option has been enabled, 1019then this character is taken to 1020be the terminal's 1021.Ic stop 1022character. 1023The initial value for the stop character is taken to be 1024the terminal's 1025.Ic stop 1026character. 1027.It Ic susp 1028If 1029.Nm 1030is in 1031.Ic localchars 1032mode, or 1033.Dv LINEMODE 1034is enabled, and the 1035.Ic suspend 1036character is typed, a 1037.Dv TELNET SUSP 1038sequence (see 1039.Ic send 1040.Ic susp 1041above) 1042is sent to the remote host. 1043The initial value for the suspend character is taken to be 1044the terminal's 1045.Ic suspend 1046character. 1047.It Ic tracefile 1048This is the file to which the output, caused by 1049.Ic netdata 1050or 1051.Ic option 1052tracing being 1053.Dv TRUE , 1054will be written. 1055If it is set to 1056.Dq Fl , 1057then tracing information will be written to standard output (the default). 1058.It Ic worderase 1059If 1060.Nm 1061is operating in 1062.Dv LINEMODE 1063or \*(Lqold line by line\*(Lq mode, then this character is taken to 1064be the terminal's 1065.Ic worderase 1066character. 1067The initial value for the worderase character is taken to be 1068the terminal's 1069.Ic worderase 1070character. 1071.It Ic \&? 1072Displays the legal 1073.Ic set 1074.Pq Ic unset 1075commands. 1076.El 1077.It Ic slc Ar state 1078The 1079.Ic slc 1080command (Set Local Characters) is used to set 1081or change the state of the special 1082characters when the 1083.Dv TELNET LINEMODE 1084option has 1085been enabled. 1086Special characters are characters that get 1087mapped to 1088.Tn TELNET 1089commands sequences (like 1090.Ic ip 1091or 1092.Ic quit ) 1093or line editing characters (like 1094.Ic erase 1095and 1096.Ic kill ) . 1097By default, the local special characters are exported. 1098.Bl -tag -width Fl 1099.It Ic check 1100Verify the current settings for the current special characters. 1101The remote side is requested to send all the current special 1102character settings, and if there are any discrepancies with 1103the local side, the local side will switch to the remote value. 1104.It Ic export 1105Switch to the local defaults for the special characters. 1106The 1107local default characters are those of the local terminal at 1108the time when 1109.Nm 1110was started. 1111.It Ic import 1112Switch to the remote defaults for the special characters. 1113The remote default characters are those of the remote system 1114at the time when the 1115.Tn TELNET 1116connection was established. 1117.It Ic \&? 1118Prints out help information for the 1119.Ic slc 1120command. 1121.El 1122.It Ic status 1123Show the current status of 1124.Nm "" . 1125This includes the peer one is connected to, as well 1126as the current mode. 1127.It Ic toggle Ar arguments ... 1128Toggle (between 1129.Dv TRUE 1130and 1131.Dv FALSE ) 1132various flags that control how 1133.Nm 1134responds to events. 1135These flags may be set explicitly to 1136.Dv TRUE 1137or 1138.Dv FALSE 1139using the 1140.Ic set 1141and 1142.Ic unset 1143commands listed above. 1144More than one argument may be specified. 1145The state of these flags may be interrogated with the 1146.Ic display 1147command. 1148Valid arguments are: 1149.Bl -tag -width Ar 1150.It Ic authdebug 1151Turns on debugging information for the authentication code. 1152.It Ic autoflush 1153If 1154.Ic autoflush 1155and 1156.Ic localchars 1157are both 1158.Dv TRUE , 1159then when the 1160.Ic ao , 1161or 1162.Ic quit 1163characters are recognized (and transformed into 1164.Tn TELNET 1165sequences; see 1166.Ic set 1167above for details), 1168.Nm 1169refuses to display any data on the user's terminal 1170until the remote system acknowledges (via a 1171.Dv TELNET TIMING MARK 1172option) 1173that it has processed those 1174.Tn TELNET 1175sequences. 1176The initial value for this toggle is 1177.Dv TRUE 1178if the terminal user had not 1179done an "stty noflsh", otherwise 1180.Dv FALSE 1181(see 1182.Xr stty 1 ) . 1183.It Ic autodecrypt 1184When the 1185.Dv TELNET ENCRYPT 1186option is negotiated, by 1187default the actual encryption (decryption) of the data 1188stream does not start automatically. 1189The autoencrypt 1190(autodecrypt) command states that encryption of the 1191output (input) stream should be enabled as soon as 1192possible. 1193.Pp 1194Note: Because of export controls, the 1195.Dv TELNET ENCRYPT 1196option is not supported outside the United States and Canada. 1197.It Ic autologin 1198If the remote side supports the 1199.Dv TELNET AUTHENTICATION 1200option 1201.Tn TELNET 1202attempts to use it to perform automatic authentication. 1203If the 1204.Dv AUTHENTICATION 1205option is not supported, the user's login 1206name are propagated through the 1207.Dv TELNET ENVIRON 1208option. 1209This command is the same as specifying the 1210.Fl a 1211option on the 1212.Ic open 1213command. 1214.It Ic autosynch 1215If 1216.Ic autosynch 1217and 1218.Ic localchars 1219are both 1220.Dv TRUE , 1221then when either the 1222.Ic intr 1223or 1224.Ic quit 1225characters is typed (see 1226.Ic set 1227above for descriptions of the 1228.Ic intr 1229and 1230.Ic quit 1231characters), the resulting 1232.Tn TELNET 1233sequence sent is followed by the 1234.Dv TELNET SYNCH 1235sequence. 1236This procedure 1237.Ic should 1238cause the remote system to begin throwing away all previously 1239typed input until both of the 1240.Tn TELNET 1241sequences have been read and acted upon. 1242The initial value of this toggle is 1243.Dv FALSE . 1244.It Ic binary 1245Enable or disable the 1246.Dv TELNET BINARY 1247option on both input and output. 1248.It Ic inbinary 1249Enable or disable the 1250.Dv TELNET BINARY 1251option on input. 1252.It Ic outbinary 1253Enable or disable the 1254.Dv TELNET BINARY 1255option on output. 1256.It Ic crlf 1257If this is 1258.Dv TRUE , 1259then carriage returns will be sent as 1260.Li \*[Lt]CR\*[Gt]\*[Lt]LF\*[Gt] . 1261If this is 1262.Dv FALSE , 1263then carriage returns will be send as 1264.Li \*[Lt]CR\*[Gt]\*[Lt]NUL\*[Gt] . 1265The initial value for this toggle is 1266.Dv FALSE . 1267.It Ic crmod 1268Toggle carriage return mode. 1269When this mode is enabled, most carriage return characters received from 1270the remote host will be mapped into a carriage return followed by 1271a line feed. 1272This mode does not affect those characters typed by the user, only 1273those received from the remote host. 1274This mode is not very useful unless the remote host 1275only sends carriage return, but never line feed. 1276The initial value for this toggle is 1277.Dv FALSE . 1278.It Ic debug 1279Toggles socket level debugging (useful only to the 1280.Ic super user ) . 1281The initial value for this toggle is 1282.Dv FALSE . 1283.It Ic encdebug 1284Turns on debugging information for the encryption code. 1285.It Ic localchars 1286If this is 1287.Dv TRUE , 1288then the 1289.Ic flush , 1290.Ic interrupt , 1291.Ic quit , 1292.Ic erase , 1293and 1294.Ic kill 1295characters (see 1296.Ic set 1297above) are recognized locally, and transformed into (hopefully) appropriate 1298.Tn TELNET 1299control sequences 1300(respectively 1301.Ic ao , 1302.Ic ip , 1303.Ic brk , 1304.Ic ec , 1305and 1306.Ic el ; 1307see 1308.Ic send 1309above). 1310The initial value for this toggle is 1311.Dv TRUE 1312in \*(Lqold line by line\*(Rq mode, 1313and 1314.Dv FALSE 1315in \*(Lqcharacter at a time\*(Rq mode. 1316When the 1317.Dv LINEMODE 1318option is enabled, the value of 1319.Ic localchars 1320is ignored, and assumed to always be 1321.Dv TRUE . 1322If 1323.Dv LINEMODE 1324has ever been enabled, then 1325.Ic quit 1326is sent as 1327.Ic abort , 1328and 1329.Ic eof and 1330.Ic suspend 1331are sent as 1332.Ic eof and 1333.Ic susp 1334(see 1335.Ic send 1336above). 1337.It Ic netdata 1338Toggles the display of all network data (in hexadecimal format). 1339The initial value for this toggle is 1340.Dv FALSE . 1341.It Ic options 1342Toggles the display of some internal 1343.Nm 1344protocol processing (having to do with 1345.Tn TELNET 1346options). 1347The initial value for this toggle is 1348.Dv FALSE . 1349.It Ic prettydump 1350When the 1351.Ic netdata 1352toggle is enabled, if 1353.Ic prettydump 1354is enabled the output from the 1355.Ic netdata 1356command will be formatted in a more user readable format. 1357Spaces are put between each character in the output, and the 1358beginning of any 1359.Tn TELNET 1360escape sequence is preceded by a '*' to aid in locating them. 1361.It Ic skiprc 1362When the skiprc toggle is 1363.Dv TRUE , 1364.Tn TELNET 1365skips the reading of the 1366.Pa \&.telnetrc 1367file in the users home 1368directory when connections are opened. 1369The initial 1370value for this toggle is 1371.Dv FALSE . 1372.It Ic termdata 1373Toggles the display of all terminal data (in hexadecimal format). 1374The initial value for this toggle is 1375.Dv FALSE . 1376.It Ic verbose_encrypt 1377When the 1378.Ic verbose_encrypt 1379toggle is 1380.Dv TRUE , 1381.Nm 1382prints out a message each time encryption is enabled or 1383disabled. 1384The initial value for this toggle is 1385.Dv FALSE . 1386Note: Because of export controls, data encryption 1387is not supported outside of the United States and Canada. 1388.It Ic \&? 1389Displays the legal 1390.Ic toggle 1391commands. 1392.El 1393.It Ic z 1394Suspend 1395.Nm "" . 1396This command only works when the user is using the 1397.Xr csh 1 . 1398.It Ic \&! Op Ar command 1399Execute a single command in a subshell on the local 1400system. 1401If 1402.Ar command 1403is omitted, then an interactive 1404subshell is invoked. 1405.It Ic \&? Op Ar command 1406Get help. 1407With no arguments, 1408.Nm 1409prints a help summary. 1410If a command is specified, 1411.Nm 1412will print the help information for just that command. 1413.El 1414.Sh ENVIRONMENT 1415.Nm 1416uses at least the 1417.Ev HOME , 1418.Ev SHELL , 1419.Ev DISPLAY , 1420and 1421.Ev TERM 1422environment variables. 1423Other environment variables may be propagated 1424to the other side via the 1425.Dv TELNET ENVIRON 1426option. 1427.Sh FILES 1428.Bl -tag -width ~/.telnetrc -compact 1429.It Pa ~/.telnetrc 1430user customized telnet startup values 1431.El 1432.Sh HISTORY 1433The 1434.Nm 1435command appeared in 1436.Bx 4.2 . 1437IPsec support was added by WIDE/KAME project, in 1999. 1438.Sh NOTES 1439On some remote systems, echo has to be turned off manually when in 1440\*(Lqold line by line\*(Rq mode. 1441.Pp 1442In \*(Lqold line by line\*(Rq mode or 1443.Dv LINEMODE 1444the terminal's 1445.Ic eof 1446character is only recognized (and sent to the remote system) 1447when it is the first character on a line. 1448