1.\" $NetBSD: telnet.1,v 1.22 2002/02/08 01:36:34 ross 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 8 47.Op Fl E 48.Op Fl F 49.Op Fl K 50.Op Fl L 51.Op Fl N 52.Bk -words 53.Op Fl S Ar tos 54.Ek 55.Bk -words 56.Op Fl X Ar authtype 57.Ek 58.Op Fl a 59.Op Fl c 60.Op Fl d 61.Bk -words 62.Op Fl e Ar escapechar 63.Ek 64.Op Fl f 65.Bk -words 66.Op Fl k Ar realm 67.Ek 68.Bk -words 69.Op Fl l Ar user 70.Ek 71.Bk -words 72.Op Fl n Ar tracefile 73.Ek 74.Bk -words 75.Op Fl P Ar policy 76.Ek 77.Op Fl r 78.Op Fl x 79.Oo 80.Ar host 81.Op Ar port 82.Oc 83.Sh DESCRIPTION 84The 85.Nm 86command 87is used to communicate with another host using the 88.Tn TELNET 89protocol. 90If 91.Nm 92is invoked without the 93.Ar host 94argument, it enters command mode, 95indicated by its prompt 96.Pq Nm telnet\&\*[Gt] . 97In this mode, it accepts and executes the commands listed below. 98If it is invoked with arguments, it performs an 99.Ic open 100command with those arguments. 101.Pp 102Options: 103.Bl -tag -width indent 104.It Fl 8 105Specifies an 8-bit data path. This causes an attempt to 106negotiate the 107.Dv TELNET BINARY 108option on both input and output. 109.It Fl E 110Stops any character from being recognized as an escape character. 111.It Fl F 112If Kerberos V5 authentication is being used, the 113.Fl F 114option allows the local credentials to be forwarded 115to the remote system, including any credentials that 116have already been forwarded into the local environment. 117.It Fl K 118Specifies no automatic login to the remote system. 119.It Fl L 120Specifies an 8-bit data path on output. This causes the 121BINARY option to be negotiated on output. 122.It Fl N 123Numeric host address. No attempt will be made to look up 124symbolic names for host addresses. 125.It Fl S Ar tos 126Sets the IP type-of-service (TOS) option for the telnet 127connection to the value 128.Ar tos , 129which can be a numeric TOS value 130or, on systems that support it, a symbolic 131TOS name found in the /etc/iptos file. 132.It Fl X Ar atype 133Disables the 134.Ar atype 135type of authentication. 136.It Fl a 137Attempt automatic login. 138Currently, this sends the user name via the 139.Ev USER 140variable 141of the 142.Ev ENVIRON 143option if supported by the remote system. 144The name used is that of the current user as returned by 145.Xr getlogin 2 146if it agrees with the current user ID, 147otherwise it is the name associated with the user ID. 148.It Fl c 149Disables the reading of the user's 150.Pa \&.telnetrc 151file. (See the 152.Ic toggle skiprc 153command on this man page.) 154.It Fl d 155Sets the initial value of the 156.Ic debug 157toggle to 158.Dv TRUE . 159.It Fl e Ar escape char 160Sets the initial 161.Nm 162escape character to 163.Ar escape char . 164If 165.Ar escape char 166is omitted, then 167there will be no escape character. 168.It Fl f 169If Kerberos V5 authentication is being used, the 170.Fl f 171option allows the local credentials to be forwarded to the remote system. 172.It Fl k Ar realm 173If Kerberos authentication is being used, the 174.Fl k 175option requests that telnet obtain tickets for the remote host in 176realm 177.Ar realm 178instead of the remote host's realm, as determined by 179.Xr krb_realmofhost 3 . 180.It Fl l Ar user 181When connecting to the remote system, if the remote system 182understands the 183.Ev ENVIRON 184option, then 185.Ar user 186will be sent to the remote system as the value for the variable USER. 187This option implies the 188.Fl a 189option. 190This option may also be used with the 191.Ic open 192command. 193.It Fl n Ar tracefile 194Opens 195.Ar tracefile 196for recording trace information. 197See the 198.Ic set tracefile 199command below. 200.It Fl P Ar policy 201Use IPsec policy specification string 202.Ar policy , 203for the connections. 204See 205.Xr ipsec_set_policy 3 206for details. 207.It Fl r 208Specifies a user interface similar to 209.Xr rlogin 1 . 210In this 211mode, the escape character is set to the tilde (~) character, 212unless modified by the 213.Fl e 214option. 215.It Fl x 216Turns on encryption of the data stream if possible. This 217option is not available outside of the United States and 218Canada. 219.It Ar host 220Indicates the official name, an alias, or the Internet address 221of a remote host. 222.It Ar port 223Indicates a port number (address of an application). If a number is 224not specified, the default 225.Nm 226port is used. 227.El 228.Pp 229When in rlogin mode, a line of the form ~. disconnects from the 230remote host; ~ is the telnet escape character. 231Similarly, the line ~^Z suspends the telnet session. 232The line ~^] escapes to the normal telnet escape prompt. 233.Pp 234Once a connection has been opened, 235.Nm 236will attempt to enable the 237.Dv TELNET LINEMODE 238option. 239If this fails, then 240.Nm 241will revert to one of two input modes: 242either \*(Lqcharacter at a time\*(Rq 243or \*(Lqold line by line\*(Rq 244depending on what the remote system supports. 245.Pp 246When 247.Dv LINEMODE 248is enabled, character processing is done on the 249local system, under the control of the remote system. When input 250editing or character echoing is to be disabled, the remote system 251will relay that information. The remote system will also relay 252changes to any special characters that happen on the remote 253system, so that they can take effect on the local system. 254.Pp 255In \*(Lqcharacter at a time\*(Rq mode, most 256text typed is immediately sent to the remote host for processing. 257.Pp 258In \*(Lqold line by line\*(Rq mode, all text is echoed locally, 259and (normally) only completed lines are sent to the remote host. 260The \*(Lqlocal echo character\*(Rq (initially \*(Lq^E\*(Rq) may be used 261to turn off and on the local echo 262(this would mostly be used to enter passwords 263without the password being echoed). 264.Pp 265If the 266.Dv LINEMODE 267option is enabled, or if the 268.Ic localchars 269toggle is 270.Dv TRUE 271(the default for \*(Lqold line by line\*(Lq; see below), 272the user's 273.Ic quit , 274.Ic intr , 275and 276.Ic flush 277characters are trapped locally, and sent as 278.Tn TELNET 279protocol sequences to the remote side. 280If 281.Dv LINEMODE 282has ever been enabled, then the user's 283.Ic susp 284and 285.Ic eof 286are also sent as 287.Tn TELNET 288protocol sequences, 289and 290.Ic quit 291is sent as a 292.Dv TELNET ABORT 293instead of 294.Dv BREAK . 295There are options (see 296.Ic toggle 297.Ic autoflush 298and 299.Ic toggle 300.Ic autosynch 301below) 302which cause this action to flush subsequent output to the terminal 303(until the remote host acknowledges the 304.Tn TELNET 305sequence) and flush previous terminal input 306(in the case of 307.Ic quit 308and 309.Ic intr ) . 310.Pp 311While connected to a remote host, 312.Nm 313command mode may be entered by typing the 314.Nm 315\*(Lqescape character\*(Rq (initially \*(Lq^]\*(Rq). 316When in command mode, the normal terminal editing conventions are available. 317.Pp 318The following 319.Nm 320commands are available. 321Only enough of each command to uniquely identify it need be typed 322(this is also true for arguments to the 323.Ic mode , 324.Ic set , 325.Ic toggle , 326.Ic unset , 327.Ic slc , 328.Ic environ , 329and 330.Ic display 331commands). 332.Pp 333.Bl -tag -width "mode type" 334.It Ic auth Ar argument ... 335The auth command manipulates the information sent through the 336.Dv TELNET AUTHENTICATE 337option. Valid arguments for the 338auth command are as follows: 339.Bl -tag -width "disable type" 340.It Ic disable Ar type 341Disables the specified type of authentication. To 342obtain a list of available types, use the 343.Ic auth disable \&? 344command. 345.It Ic enable Ar type 346Enables the specified type of authentication. To 347obtain a list of available types, use the 348.Ic auth enable \&? 349command. 350.It Ic status 351Lists the current status of the various types of 352authentication. 353.El 354.It Ic close 355Close a 356.Tn TELNET 357session and return to command mode. 358.It Ic display Ar argument ... 359Displays all, or some, of the 360.Ic set 361and 362.Ic toggle 363values (see below). 364.It Ic encrypt Ar argument ... 365The encrypt command manipulates the information sent through the 366.Dv TELNET ENCRYPT 367option. 368.Pp 369Note: Because of export controls, the 370.Dv TELNET ENCRYPT 371option is not supported outside of the United States and Canada. 372.Pp 373Valid arguments for the encrypt command are: 374.Bl -tag -width Ar 375.It Ic disable Ar type Ic [input|output] 376Disables the specified type of encryption. If you 377omit the input and output, both input and output 378are disabled. To obtain a list of available 379types, use the 380.Ic encrypt disable \&? 381command. 382.It Ic enable Ar type Ic [input|output] 383Enables the specified type of encryption. If you 384omit input and output, both input and output are 385enabled. To obtain a list of available types, use the 386.Ic encrypt enable \&? 387command. 388.It Ic input 389This is the same as the 390.Ic encrypt start input 391command. 392.It Ic -input 393This is the same as the 394.Ic encrypt stop input 395command. 396.It Ic output 397This is the same as the 398.Ic encrypt start output 399command. 400.It Ic -output 401This is the same as the 402.Ic encrypt stop output 403command. 404.It Ic start Ic [input|output] 405Attempts to start encryption. If you omit 406.Ic input 407and 408.Ic output , 409both input and output are enabled. To 410obtain a list of available types, use the 411.Ic encrypt enable \&? 412command. 413.It Ic status 414Lists the current status of encryption. 415.It Ic stop Ic [input|output] 416Stops encryption. If you omit input and output, 417encryption is on both input and output. 418.It Ic type Ar type 419Sets the default type of encryption to be used 420with later 421.Ic encrypt start 422or 423.Ic encrypt stop 424commands. 425.El 426.It Ic environ Ar arguments ... 427The 428.Ic environ 429command is used to manipulate the 430variables that may be sent through the 431.Dv TELNET ENVIRON 432option. 433The initial set of variables is taken from the users 434environment, with only the 435.Ev DISPLAY 436and 437.Ev PRINTER 438variables being exported by default. 439The 440.Ev USER 441variable is also exported if the 442.Fl a 443or 444.Fl l 445options are used. 446.Pp 447Valid arguments for the 448.Ic environ 449command are: 450.Bl -tag -width Fl 451.It Ic define Ar variable value 452Define the variable 453.Ar variable 454to have a value of 455.Ar value . 456Any variables defined by this command are automatically exported. 457The 458.Ar value 459may be enclosed in single or double quotes so 460that tabs and spaces may be included. 461.It Ic undefine Ar variable 462Remove 463.Ar variable 464from the list of environment variables. 465.It Ic export Ar variable 466Mark the variable 467.Ar variable 468to be exported to the remote side. 469.It Ic unexport Ar variable 470Mark the variable 471.Ar variable 472to not be exported unless 473explicitly asked for by the remote side. 474.It Ic list 475List the current set of environment variables. 476Those marked with a 477.Cm * 478will be sent automatically, 479other variables will only be sent if explicitly requested. 480.It Ic \&? 481Prints out help information for the 482.Ic environ 483command. 484.El 485.It Ic logout 486Sends the 487.Dv TELNET LOGOUT 488option to the remote side. 489This command is similar to a 490.Ic close 491command; however, if the remote side does not support the 492.Dv LOGOUT 493option, nothing happens. 494If, however, the remote side does support the 495.Dv LOGOUT 496option, this command should cause the remote side to close the 497.Tn TELNET 498connection. 499If the remote side also supports the concept of 500suspending a user's session for later reattachment, 501the logout argument indicates that you 502should terminate the session immediately. 503.It Ic mode Ar type 504.Ar Type 505is one of several options, depending on the state of the 506.Tn TELNET 507session. 508The remote host is asked for permission to go into the requested mode. 509If the remote host is capable of entering that mode, the requested 510mode will be entered. 511.Bl -tag -width Ar 512.It Ic character 513Disable the 514.Dv TELNET LINEMODE 515option, or, if the remote side does not understand the 516.Dv LINEMODE 517option, then enter \*(Lqcharacter at a time\*(Lq mode. 518.It Ic line 519Enable the 520.Dv TELNET LINEMODE 521option, or, if the remote side does not understand the 522.Dv LINEMODE 523option, then attempt to enter \*(Lqold-line-by-line\*(Lq mode. 524.It Ic isig Pq Ic \-isig 525Attempt to enable (disable) the 526.Dv TRAPSIG 527mode of the 528.Dv LINEMODE 529option. 530This requires that the 531.Dv LINEMODE 532option be enabled. 533.It Ic edit Pq Ic \-edit 534Attempt to enable (disable) the 535.Dv EDIT 536mode of the 537.Dv LINEMODE 538option. 539This requires that the 540.Dv LINEMODE 541option be enabled. 542.It Ic softtabs Pq Ic \-softtabs 543Attempt to enable (disable) the 544.Dv SOFT_TAB 545mode of the 546.Dv LINEMODE 547option. 548This requires that the 549.Dv LINEMODE 550option be enabled. 551.It Ic litecho Pq Ic \-litecho 552Attempt to enable (disable) the 553.Dv LIT_ECHO 554mode of the 555.Dv LINEMODE 556option. 557This requires that the 558.Dv LINEMODE 559option be enabled. 560.It Ic \&? 561Prints out help information for the 562.Ic mode 563command. 564.El 565.It Xo 566.Ic open Ar host 567.Op Fl l Ar user 568.Op Fl a 569.Oo Op \&- Ns 570.Ar port Oc 571.Xc 572Open a connection to the named host. 573If no port number 574is specified, 575.Nm 576will attempt to contact a 577.Tn TELNET 578server at the default port. 579The host specification may be either a host name (see 580.Xr hosts 5 ) 581or an Internet address specified in the \*(Lqdot notation\*(Rq (see 582.Xr inet 3 ) . 583The 584.Fl l 585option may be used to specify the user name 586to be passed to the remote system via the 587.Ev ENVIRON 588option. 589If a port is specified 590.Nm 591omits any automatic initialisation of 592.Tn TELNET 593options. When the port number is preceded by a minus sign, 594the initial option negotiation is done. 595After establishing a connection, the file 596.Pa \&.telnetrc 597in the 598user's home directory is opened. Lines beginning with a # are 599comment lines. Blank lines are ignored. Lines that begin 600without white space are the start of a machine entry. The 601first thing on the line is the name of the machine that is 602being connected to. The rest of the line, and successive 603lines that begin with white space are assumed to be 604.Nm 605commands and are processed as if they had been typed 606in manually to the 607.Nm 608command prompt. 609Commands associated with the special machine entry 610.Dv DEFAULT 611are processed for any given host. 612.It Ic quit 613Close any open 614.Tn TELNET 615session and exit 616.Nm "" . 617An end of file (in command mode) will also close a session and exit. 618.It Ic send Ar arguments 619Sends one or more special character sequences to the remote host. 620The following are the arguments which may be specified 621(more than one argument may be specified at a time): 622.Pp 623.Bl -tag -width escape 624.It Ic abort 625Sends the 626.Dv TELNET ABORT 627(Abort 628processes) 629sequence. 630.It Ic ao 631Sends the 632.Dv TELNET AO 633(Abort Output) sequence, which should cause the remote system to flush 634all output 635.Em from 636the remote system 637.Em to 638the user's terminal. 639.It Ic ayt 640Sends the 641.Dv TELNET AYT 642(Are You There) 643sequence, to which the remote system may or may not choose to respond. 644.It Ic brk 645Sends the 646.Dv TELNET BRK 647(Break) sequence, which may have significance to the remote 648system. 649.It Ic ec 650Sends the 651.Dv TELNET EC 652(Erase Character) 653sequence, which should cause the remote system to erase the last character 654entered. 655.It Ic el 656Sends the 657.Dv TELNET EL 658(Erase Line) 659sequence, which should cause the remote system to erase the line currently 660being entered. 661.It Ic eof 662Sends the 663.Dv TELNET EOF 664(End Of File) 665sequence. 666.It Ic eor 667Sends the 668.Dv TELNET EOR 669(End of Record) 670sequence. 671.It Ic escape 672Sends the current 673.Nm 674escape character (initially \*(Lq^\*(Rq). 675.It Ic ga 676Sends the 677.Dv TELNET GA 678(Go Ahead) 679sequence, which likely has no significance to the remote system. 680.It Ic getstatus 681If the remote side supports the 682.Dv TELNET STATUS 683command, 684.Ic getstatus 685will send the subnegotiation to request that the server send 686its current option status. 687.It Ic ip 688Sends the 689.Dv TELNET IP 690(Interrupt Process) sequence, which should cause the remote 691system to abort the currently running process. 692.It Ic nop 693Sends the 694.Dv TELNET NOP 695(No OPeration) 696sequence. 697.It Ic susp 698Sends the 699.Dv TELNET SUSP 700(SUSPend process) 701sequence. 702.It Ic synch 703Sends the 704.Dv TELNET SYNCH 705sequence. 706This sequence causes the remote system to discard all previously typed 707(but not yet read) input. 708This sequence is sent as 709.Tn TCP 710urgent 711data (and may not work if the remote system is a 712.Bx 4.2 713system -- if 714it doesn't work, a lower case \*(Lqr\*(Rq may be echoed on the terminal). 715.It Ic do Ar cmd 716.It Ic dont Ar cmd 717.It Ic will Ar cmd 718.It Ic wont Ar cmd 719Sends the 720.Dv TELNET DO 721.Ar cmd 722sequence. 723.Ar Cmd 724can be either a decimal number between 0 and 255, 725or a symbolic name for a specific 726.Dv TELNET 727command. 728.Ar Cmd 729can also be either 730.Ic help 731or 732.Ic \&? 733to print out help information, including 734a list of known symbolic names. 735.It Ic \&? 736Prints out help information for the 737.Ic send 738command. 739.El 740.It Ic set Ar argument value 741.It Ic unset Ar argument value 742The 743.Ic set 744command will set any one of a number of 745.Nm 746variables to a specific value or to 747.Dv TRUE . 748The special value 749.Ic off 750turns off the function associated with 751the variable, this is equivalent to using the 752.Ic unset 753command. 754The 755.Ic unset 756command will disable or set to 757.Dv FALSE 758any of the specified functions. 759The values of variables may be interrogated with the 760.Ic display 761command. 762The variables which may be set or unset, but not toggled, are 763listed here. In addition, any of the variables for the 764.Ic toggle 765command may be explicitly set or unset using 766the 767.Ic set 768and 769.Ic unset 770commands. 771.Bl -tag -width escape 772.It Ic ayt 773If 774.Tn TELNET 775is in localchars mode, or 776.Dv LINEMODE 777is enabled, and the status character is typed, a 778.Dv TELNET AYT 779sequence (see 780.Ic send ayt 781above) is sent to the 782remote host. The initial value for the "Are You There" 783character is the terminal's status character. 784.It Ic echo 785This is the value (initially \*(Lq^E\*(Rq) which, when in 786\*(Lqline by line\*(Rq mode, toggles between doing local echoing 787of entered characters (for normal processing), and suppressing 788echoing of entered characters (for entering, say, a password). 789.It Ic eof 790If 791.Nm 792is operating in 793.Dv LINEMODE 794or \*(Lqold line by line\*(Rq mode, entering this character 795as the first character on a line will cause this character to be 796sent to the remote system. 797The initial value of the eof character is taken to be the terminal's 798.Ic eof 799character. 800.It Ic erase 801If 802.Nm 803is in 804.Ic localchars 805mode (see 806.Ic toggle 807.Ic localchars 808below), 809.Sy and 810if 811.Nm 812is operating in \*(Lqcharacter at a time\*(Rq mode, then when this 813character is typed, a 814.Dv TELNET EC 815sequence (see 816.Ic send 817.Ic ec 818above) 819is sent to the remote system. 820The initial value for the erase character is taken to be 821the terminal's 822.Ic erase 823character. 824.It Ic escape 825This is the 826.Nm 827escape character (initially \*(Lq^[\*(Rq) which causes entry 828into 829.Nm 830command mode (when connected to a remote system). 831.It Ic flushoutput 832If 833.Nm 834is in 835.Ic localchars 836mode (see 837.Ic toggle 838.Ic localchars 839below) 840and the 841.Ic flushoutput 842character is typed, a 843.Dv TELNET AO 844sequence (see 845.Ic send 846.Ic ao 847above) 848is sent to the remote host. 849The initial value for the flush character is taken to be 850the terminal's 851.Ic flush 852character. 853.It Ic forw1 854.It Ic forw2 855If 856.Tn TELNET 857is operating in 858.Dv LINEMODE , 859these are the 860characters that, when typed, cause partial lines to be 861forwarded to the remote system. The initial value for 862the forwarding characters are taken from the terminal's 863eol and eol2 characters. 864.It Ic interrupt 865If 866.Nm 867is in 868.Ic localchars 869mode (see 870.Ic toggle 871.Ic localchars 872below) 873and the 874.Ic interrupt 875character is typed, a 876.Dv TELNET IP 877sequence (see 878.Ic send 879.Ic ip 880above) 881is sent to the remote host. 882The initial value for the interrupt character is taken to be 883the terminal's 884.Ic intr 885character. 886.It Ic kill 887If 888.Nm 889is in 890.Ic localchars 891mode (see 892.Ic toggle 893.Ic localchars 894below), 895.Ic and 896if 897.Nm 898is operating in \*(Lqcharacter at a time\*(Rq mode, then when this 899character is typed, a 900.Dv TELNET EL 901sequence (see 902.Ic send 903.Ic el 904above) 905is sent to the remote system. 906The initial value for the kill character is taken to be 907the terminal's 908.Ic kill 909character. 910.It Ic lnext 911If 912.Nm 913is operating in 914.Dv LINEMODE 915or \*(Lqold line by line\*(Lq mode, then this character is taken to 916be the terminal's 917.Ic lnext 918character. 919The initial value for the lnext character is taken to be 920the terminal's 921.Ic lnext 922character. 923.It Ic quit 924If 925.Nm 926is in 927.Ic localchars 928mode (see 929.Ic toggle 930.Ic localchars 931below) 932and the 933.Ic quit 934character is typed, a 935.Dv TELNET BRK 936sequence (see 937.Ic send 938.Ic brk 939above) 940is sent to the remote host. 941The initial value for the quit character is taken to be 942the terminal's 943.Ic quit 944character. 945.It Ic reprint 946If 947.Nm 948is operating in 949.Dv LINEMODE 950or \*(Lqold line by line\*(Lq mode, then this character is taken to 951be the terminal's 952.Ic reprint 953character. 954The initial value for the reprint character is taken to be 955the terminal's 956.Ic reprint 957character. 958.It Ic rlogin 959This is the rlogin escape character. 960If set, the normal 961.Tn TELNET 962escape character is ignored unless it is 963preceded by this character at the beginning of a line. 964This character, at the beginning of a line followed by 965a "." closes the connection; when followed by a ^Z it 966suspends the 967.Nm 968command. The initial state is to 969disable the rlogin escape character. 970.It Ic start 971If the 972.Dv TELNET TOGGLE-FLOW-CONTROL 973option has been enabled, 974then this character is taken to 975be the terminal's 976.Ic start 977character. 978The initial value for the start character is taken to be 979the terminal's 980.Ic start 981character. 982.It Ic stop 983If the 984.Dv TELNET TOGGLE-FLOW-CONTROL 985option has been enabled, 986then this character is taken to 987be the terminal's 988.Ic stop 989character. 990The initial value for the stop character is taken to be 991the terminal's 992.Ic stop 993character. 994.It Ic susp 995If 996.Nm 997is in 998.Ic localchars 999mode, or 1000.Dv LINEMODE 1001is enabled, and the 1002.Ic suspend 1003character is typed, a 1004.Dv TELNET SUSP 1005sequence (see 1006.Ic send 1007.Ic susp 1008above) 1009is sent to the remote host. 1010The initial value for the suspend character is taken to be 1011the terminal's 1012.Ic suspend 1013character. 1014.It Ic tracefile 1015This is the file to which the output, caused by 1016.Ic netdata 1017or 1018.Ic option 1019tracing being 1020.Dv TRUE , 1021will be written. If it is set to 1022.Dq Fl , 1023then tracing information will be written to standard output (the default). 1024.It Ic worderase 1025If 1026.Nm 1027is operating in 1028.Dv LINEMODE 1029or \*(Lqold line by line\*(Lq mode, then this character is taken to 1030be the terminal's 1031.Ic worderase 1032character. 1033The initial value for the worderase character is taken to be 1034the terminal's 1035.Ic worderase 1036character. 1037.It Ic \&? 1038Displays the legal 1039.Ic set 1040.Pq Ic unset 1041commands. 1042.El 1043.It Ic slc Ar state 1044The 1045.Ic slc 1046command (Set Local Characters) is used to set 1047or change the state of the special 1048characters when the 1049.Dv TELNET LINEMODE 1050option has 1051been enabled. Special characters are characters that get 1052mapped to 1053.Tn TELNET 1054commands sequences (like 1055.Ic ip 1056or 1057.Ic quit ) 1058or line editing characters (like 1059.Ic erase 1060and 1061.Ic kill ) . 1062By default, the local special characters are exported. 1063.Bl -tag -width Fl 1064.It Ic check 1065Verify the current settings for the current special characters. 1066The remote side is requested to send all the current special 1067character settings, and if there are any discrepancies with 1068the local side, the local side will switch to the remote value. 1069.It Ic export 1070Switch to the local defaults for the special characters. The 1071local default characters are those of the local terminal at 1072the time when 1073.Nm 1074was started. 1075.It Ic import 1076Switch to the remote defaults for the special characters. 1077The remote default characters are those of the remote system 1078at the time when the 1079.Tn TELNET 1080connection was established. 1081.It Ic \&? 1082Prints out help information for the 1083.Ic slc 1084command. 1085.El 1086.It Ic status 1087Show the current status of 1088.Nm "" . 1089This includes the peer one is connected to, as well 1090as the current mode. 1091.It Ic toggle Ar arguments ... 1092Toggle (between 1093.Dv TRUE 1094and 1095.Dv FALSE ) 1096various flags that control how 1097.Nm 1098responds to events. 1099These flags may be set explicitly to 1100.Dv TRUE 1101or 1102.Dv FALSE 1103using the 1104.Ic set 1105and 1106.Ic unset 1107commands listed above. 1108More than one argument may be specified. 1109The state of these flags may be interrogated with the 1110.Ic display 1111command. 1112Valid arguments are: 1113.Bl -tag -width Ar 1114.It Ic authdebug 1115Turns on debugging information for the authentication code. 1116.It Ic autoflush 1117If 1118.Ic autoflush 1119and 1120.Ic localchars 1121are both 1122.Dv TRUE , 1123then when the 1124.Ic ao , 1125or 1126.Ic quit 1127characters are recognized (and transformed into 1128.Tn TELNET 1129sequences; see 1130.Ic set 1131above for details), 1132.Nm 1133refuses to display any data on the user's terminal 1134until the remote system acknowledges (via a 1135.Dv TELNET TIMING MARK 1136option) 1137that it has processed those 1138.Tn TELNET 1139sequences. 1140The initial value for this toggle is 1141.Dv TRUE 1142if the terminal user had not 1143done an "stty noflsh", otherwise 1144.Dv FALSE 1145(see 1146.Xr stty 1 ) . 1147.It Ic autodecrypt 1148When the 1149.Dv TELNET ENCRYPT 1150option is negotiated, by 1151default the actual encryption (decryption) of the data 1152stream does not start automatically. The autoencrypt 1153(autodecrypt) command states that encryption of the 1154output (input) stream should be enabled as soon as 1155possible. 1156.Pp 1157Note: Because of export controls, the 1158.Dv TELNET ENCRYPT 1159option is not supported outside the United States and Canada. 1160.It Ic autologin 1161If the remote side supports the 1162.Dv TELNET AUTHENTICATION 1163option 1164.Tn TELNET 1165attempts to use it to perform automatic authentication. If the 1166.Dv AUTHENTICATION 1167option is not supported, the user's login 1168name are propagated through the 1169.Dv TELNET ENVIRON 1170option. 1171This command is the same as specifying the 1172.Fl a 1173option on the 1174.Ic open 1175command. 1176.It Ic autosynch 1177If 1178.Ic autosynch 1179and 1180.Ic localchars 1181are both 1182.Dv TRUE , 1183then when either the 1184.Ic intr 1185or 1186.Ic quit 1187characters is typed (see 1188.Ic set 1189above for descriptions of the 1190.Ic intr 1191and 1192.Ic quit 1193characters), the resulting 1194.Tn TELNET 1195sequence sent is followed by the 1196.Dv TELNET SYNCH 1197sequence. 1198This procedure 1199.Ic should 1200cause the remote system to begin throwing away all previously 1201typed input until both of the 1202.Tn TELNET 1203sequences have been read and acted upon. 1204The initial value of this toggle is 1205.Dv FALSE . 1206.It Ic binary 1207Enable or disable the 1208.Dv TELNET BINARY 1209option on both input and output. 1210.It Ic inbinary 1211Enable or disable the 1212.Dv TELNET BINARY 1213option on input. 1214.It Ic outbinary 1215Enable or disable the 1216.Dv TELNET BINARY 1217option on output. 1218.It Ic crlf 1219If this is 1220.Dv TRUE , 1221then carriage returns will be sent as 1222.Li \*[Lt]CR\*[Gt]\*[Lt]LF\*[Gt] . 1223If this is 1224.Dv FALSE , 1225then carriage returns will be send as 1226.Li \*[Lt]CR\*[Gt]\*[Lt]NUL\*[Gt] . 1227The initial value for this toggle is 1228.Dv FALSE . 1229.It Ic crmod 1230Toggle carriage return mode. 1231When this mode is enabled, most carriage return characters received from 1232the remote host will be mapped into a carriage return followed by 1233a line feed. 1234This mode does not affect those characters typed by the user, only 1235those received from the remote host. 1236This mode is not very useful unless the remote host 1237only sends carriage return, but never line feed. 1238The initial value for this toggle is 1239.Dv FALSE . 1240.It Ic debug 1241Toggles socket level debugging (useful only to the 1242.Ic super user ) . 1243The initial value for this toggle is 1244.Dv FALSE . 1245.It Ic encdebug 1246Turns on debugging information for the encryption code. 1247.It Ic localchars 1248If this is 1249.Dv TRUE , 1250then the 1251.Ic flush , 1252.Ic interrupt , 1253.Ic quit , 1254.Ic erase , 1255and 1256.Ic kill 1257characters (see 1258.Ic set 1259above) are recognized locally, and transformed into (hopefully) appropriate 1260.Tn TELNET 1261control sequences 1262(respectively 1263.Ic ao , 1264.Ic ip , 1265.Ic brk , 1266.Ic ec , 1267and 1268.Ic el ; 1269see 1270.Ic send 1271above). 1272The initial value for this toggle is 1273.Dv TRUE 1274in \*(Lqold line by line\*(Rq mode, 1275and 1276.Dv FALSE 1277in \*(Lqcharacter at a time\*(Rq mode. 1278When the 1279.Dv LINEMODE 1280option is enabled, the value of 1281.Ic localchars 1282is ignored, and assumed to always be 1283.Dv TRUE . 1284If 1285.Dv LINEMODE 1286has ever been enabled, then 1287.Ic quit 1288is sent as 1289.Ic abort , 1290and 1291.Ic eof and 1292.Ic suspend 1293are sent as 1294.Ic eof and 1295.Ic susp 1296(see 1297.Ic send 1298above). 1299.It Ic netdata 1300Toggles the display of all network data (in hexadecimal format). 1301The initial value for this toggle is 1302.Dv FALSE . 1303.It Ic options 1304Toggles the display of some internal 1305.Nm 1306protocol processing (having to do with 1307.Tn TELNET 1308options). 1309The initial value for this toggle is 1310.Dv FALSE . 1311.It Ic prettydump 1312When the 1313.Ic netdata 1314toggle is enabled, if 1315.Ic prettydump 1316is enabled the output from the 1317.Ic netdata 1318command will be formatted in a more user readable format. 1319Spaces are put between each character in the output, and the 1320beginning of any 1321.Tn TELNET 1322escape sequence is preceded by a '*' to aid in locating them. 1323.It Ic skiprc 1324When the skiprc toggle is 1325.Dv TRUE , 1326.Tn TELNET 1327skips the reading of the 1328.Pa \&.telnetrc 1329file in the users home 1330directory when connections are opened. The initial 1331value for this toggle is 1332.Dv FALSE . 1333.It Ic termdata 1334Toggles the display of all terminal data (in hexadecimal format). 1335The initial value for this toggle is 1336.Dv FALSE . 1337.It Ic verbose_encrypt 1338When the 1339.Ic verbose_encrypt 1340toggle is 1341.Dv TRUE , 1342.Nm 1343prints out a message each time encryption is enabled or 1344disabled. The initial value for this toggle is 1345.Dv FALSE . 1346Note: Because of export controls, data encryption 1347is not supported outside of the United States and Canada. 1348.It Ic \&? 1349Displays the legal 1350.Ic toggle 1351commands. 1352.El 1353.It Ic z 1354Suspend 1355.Nm "" . 1356This command only works when the user is using the 1357.Xr csh 1 . 1358.It Ic \&! Op Ar command 1359Execute a single command in a subshell on the local 1360system. If 1361.Ar command 1362is omitted, then an interactive 1363subshell is invoked. 1364.It Ic \&? Op Ar command 1365Get help. With no arguments, 1366.Nm 1367prints a help summary. 1368If a command is specified, 1369.Nm 1370will print the help information for just that command. 1371.El 1372.Sh ENVIRONMENT 1373.Nm 1374uses at least the 1375.Ev HOME , 1376.Ev SHELL , 1377.Ev DISPLAY , 1378and 1379.Ev TERM 1380environment variables. 1381Other environment variables may be propagated 1382to the other side via the 1383.Dv TELNET ENVIRON 1384option. 1385.Sh FILES 1386.Bl -tag -width ~/.telnetrc -compact 1387.It Pa ~/.telnetrc 1388user customized telnet startup values 1389.El 1390.Sh HISTORY 1391The 1392.Nm 1393command appeared in 1394.Bx 4.2 . 1395IPsec support was added by WIDE/KAME project, in 1999. 1396.Sh NOTES 1397On some remote systems, echo has to be turned off manually when in 1398\*(Lqold line by line\*(Rq mode. 1399.Pp 1400In \*(Lqold line by line\*(Rq mode or 1401.Dv LINEMODE 1402the terminal's 1403.Ic eof 1404character is only recognized (and sent to the remote system) 1405when it is the first character on a line. 1406