Cisco IOS Terminal Services Command Reference, Release 12.3 T
Terminal Services Commands: skip through tn3270

Table Of Contents

skip (ruleset)

slip

substitute (ruleset)

telnet

telnet break-on-ip

telnet refuse-negotiations

telnet speed

telnet sync-on-break

telnet transparent

terminal lat out-group

terminal lat remote-modification

terminal transport preferred

test (ruleset)

test translate

tn3270

tn3270 8bit display

tn3270 8bit transparent-mode

tn3270 character-map

tn3270 datastream

tn3270 null-processing

tn3270 optimize-cursor-move

tn3270 reset-required

tn3270 status-message

tn3270 typeahead


skip (ruleset)

To identify a connection to ignore by the translation ruleset, use the skip command in translate ruleset configuration mode. To remove the test operation, use one of the two no forms of this command.

skip [line-number] incoming-connection-parameter regular-expression [line-number incoming-connection-parameter regular-expression [...]]

no skip incoming-connection-parameter regular-expression [incoming-connection-parameter regular-expression [...]]

no skip line-number

Syntax Description

line-number

(Optional) The line in the translation ruleset to test for a skip operation.

incoming-connection-parameter

Incoming protocol parameter to test for; up to six skip tests can be written on one command line. Parameters are available for packet assembler/disassembler (PAD) and Telnet connections, and are listed in Table 39 and Table 40.

regular-expression

Pattern with regular expression to test for ignoring.


Defaults

No default behavior or values

Command Modes

Translate ruleset configuration

Command History

Release
Modification

12.3(8)T

This command was introduced.


Usage Guidelines

Up to six skip tests can be written on one command line. The ellipses in the format shown above means multiple skip tests can be written in a translation ruleset statement.

For incoming connection attempts, a template is configured, and within the template a connection can be identified by tests written using Cisco regular expressions and a pattern that is ignored (skipped).

The translation ruleset templates have line numbers that can be displayed using the show translate ruleset EXEC command.

Cisco regular expressions are described in Appendix A, "Regular Expressions," in the Cisco IOS Terminal Services Configuration Guide.

Table 39 and Table 40 list the protocol parameter keywords and arguments that can be specified in the skip statements for incoming PAD and Telnet connections.

Table 39 Skip Keywords for Incoming PAD Connections

Keyword
Description

cud ASCII-string

Call user data (CUD) that occurs after the protocol identification (PID). For outgoing PAD connections, this is the optional, user-specified text included in the outgoing call request packet after the protocol identification bytes. The CUD is entered as an ASCII string.

dest-addr address

Destination X.121 address entered as a number from 0 to 15 digits long.

dest-addr-ext address

Network service access point (NSAP) destination address extension.

dlci number

Frame Relay data-link connection identifier (DLCI) of an Annex G service entered as a number from one to seven digits, although a size of two to four digits is more likely, or the NULL string if not received on an Annex G service.

interface type number

Interface to be used for the circuit, entered using standard Cisco IOS interface designations: Serial1/0:1, for example.

mac address

Connection-Mode Network Service (CMNS) service remote host MAC address entered as three hexadecimal numbers of four digits separated by a period, 0000.fc08.12ab, for example, or the NULL string if not received on a CMNS service.

packetsize size

X.25 maximum data packet sizes to request, entered as two numbers from the following choices: 16, 32, 64, 128, 256, 512, 1024, 2048, 4096.

pid byte-string

PID string specified in ASCII or hexadecimal. A hexadecimal PID must be prefixed by "0x." For example, 0x01000000 is the standard PAD PID. Although it is available for specifying a nonstandard Call PID, this parameter is not restricted to the common PID length and can be used to specify the entire user data field.

reversed flag

Flag to indicate whether a reverse charged Call is permitted. This flag applies to a switched virtual circuit (SVC) and is entered as a single character, Y or N, for yes or no.

source-addr address

Source X.121 address.

source-addr-ext address

NSAP source address extension.

windowsize size

X.25 window sizes to request, entered as two numbers in a range from 1 to 127.

xot-dest-addr address

Destination IP address of an X.25 over TCP (XOT) service entered in standard IP address dotted decimal notation (10.0.0.127, for example) or the NULL string if not received on an XOT service.

xot-source-addr address

Source IP address of an XOT service entered in standard IP address dotted decimal notation (10.0.0.127, for example) or the NULL string if not received on an XOT service.


Table 40 Skip Keywords for Incoming Telnet Connections

Keyword
Description

dest-addr address

Destination IP address entered in standard IP address dotted decimal notation: 10.0.0.127, for example.

dest-port port

Destination port entered as a decimal number from one to five digits long.

source-addr address

Source IP address entered in standard IP address dotted decimal notation: 10.0.0.127, for example.


Examples

The following example shows how to write match and skip tests to skip connection attempts from any subnetwork address starting with 10 or 11 and match only those with a specific IP address and destination port number:

translate ruleset customer-case-1 from telnet to pad
 ! Ignore an incoming Telnet attempt from any subnetwork address starting with 10
 skip source-addr ^10\.*
 ! Match an incoming Telnet attempt destined for an IP addresses starting 
 ! with 172.18., and a 5-digit port starting with 10 or 11
 match dest-addr ^172\.18\..* dest-port ^1[0-1]...$
 ! Or match an incoming Telnet attempt destined an IP addresses starting 
 ! with 172.18., and a 5-digit port starting with 120 through 127
 match dest-addr ^172\.18\..* dest-port ^12[0-7]..$

The following example shows how to write match and skip tests to skip connection attempts from destination 55554 and to match only those with destination addresses from 55550 to 55553 and from 55556 to 55559:

translate ruleset A from pad to telnet 
 skip dest-addr ^55554$ 
 match dest-addr ^5555.$ 

Related Commands

Command
Description

description (ruleset)

Adds a description about a translation ruleset.

match (ruleset)

Identifies a connection for processing by the translation ruleset.

options (ruleset)

Specifies protocol translation options in a translation ruleset.

set (ruleset)

Unconditionally sets one or more connection parameters to a fixed value for a translation ruleset.

show translate ruleset

Displays a summary of a specific or of all configured translation rulesets, behavioral parameters, and usage statistic.

substitute (ruleset)

Matches an available protocol and substitutes another in a translation ruleset.

test (ruleset)

Tests parameter values in a translation ruleset using regular expressions.

test translate

Displays a trace of protocol translation behavior for a connection attempt.

translate ruleset

Defines a unique name for a translation ruleset, specifies translated protocols, and enters translate ruleset configuration mode.

x25 pvc translate ruleset

Configures PVCs that are valid for protocol translation ruleset handling.


slip

To start a serial connection to a remote host by using Serial Line Internet Protocol (SLIP), use the slip command in EXEC mode.

slip [/default] {remote-ip-address | remote-name} [@tacacs-server] [/routing]} [/compressed]

Syntax Description

/default

(Optional) Makes a SLIP connection when a default address has been configured.

remote-ip-address

IP address of the client workstation or PC.

remote-name

Name of the client workstation or PC.

@tacacs-server

(Optional) IP address or IP host name of the TACACS server to which your TACACS authentication request is sent.

/routing

(Optional) Indicates that the remote system is a router. Line must be configured for asynchronous routing using SLIP encapsulation.

/compressed

(Optional) Indicates that IP header compression should be negotiated.


Command Modes

EXEC

Command History

Release
Modification

10.0

This command was introduced in a release prior to Cisco IOS Release 10.0.


Usage Guidelines

When you connect from a remote node computer to the EXEC facility on a router and want to connect from the router to a device on the network, issue the slip command.

If you specify an address for the TACACS server by using /default or tacacs-server arguments, the address must be the first parameter in the command after you enter slip. If you do not specify an address or enter /default, you are prompted for an IP address or host name. You can enter the /default keyword at this point.

If you do not use the tacacs-server argument to specify a TACACS server for SLIP address authentication, the TACACS server specified at login (if any) is used for the SLIP address query.

To optimize bandwidth on a line, SLIP enables compression of the SLIP packets using Van Jacobson TCP header compression as defined in RFC 1144.

Your system administrator must configure the system with the ip tcp header-compression passive command for the /compressed command option to be valid in EXEC mode. The ip tcp header-compression command forces header compression on or off. The default is to not compress the packets. The configuration file must have header compression on and the slip /compressed EXEC command must be entered for header compression to occur.

To terminate a session initiated with the slip command, disconnect from the device on the network using the command specific to that device. Then, exit from EXEC mode by using the exit command.

Examples

The following example makes a connection when a default IP address is assigned. Once a correct password is entered, you are placed in SLIP mode, and the IP address is displayed.

Router> slip
Password:
Entering SLIP mode.
Your IP address is 192.168.7.28, MTU is 1524 bytes

The following example illustrates the prompts displayed and the response required when you use dynamic addressing to assign the SLIP address:

Router> slip
IP address or hostname? 192.168.6.15
Password:
Entering SLIP mode
Your IP address is 192.168.6.15, MTU is 1524 bytes

In the preceding example, the address 172.31.6.15 has been assigned as the default. Password verification is still required before SLIP mode can be enabled.

Router> slip /default
Password:
Entering SLIP mode
Your IP address is 192.168.6.15, MTU is 1524 bytes

The following example illustrates the implementation of header compression on the interface with the IP address 172.24.2.1:

Router> slip 172.24.2.1 /compressed
Password:
Entering SLIP mode.
Interface IP address is 172.24.2.1, MTU is 1500 bytes.
Header compression will match your system.

In the preceding example, the interface is configured for the ip tcp header-compression passive command, which permits the user to enter the /compressed keyword at the EXEC mode prompt. The message "Header compression will match your system" indicates that the user specified compression. If the line was configured for the ip tcp header-compression on command, this line would read "Header compression is On."

The following example specifies a TACACS server named server1 for address authentication:

Router> slip 10.0.0.1@server1
Password:
Entering SLIP mode.
Interface IP address is 10.0.0.1, MTU is 1500 bytes
Header compression will match your system. 

Related Commands

Command
Description

ip tcp header-compression

Enables TCP header compression.


substitute (ruleset)

To match an available protocol and substitute another in a translation ruleset, use the substitute command in translate ruleset configuration mode. To change or remove the substitution statement, use one of the no forms of this command.

substitute [line-number] {pad | telnet} variable-parameter reg-exp-match into {pad | telnet} variable-parameter [reg-exp-write]

no substitute {pad | telnet} variable-parameter reg-exp-match into {pad | telnet} variable-parameter [reg-exp-write]

no substitute line-number ...

Syntax Description

line-number

(Optional) The line in the translation ruleset to test for substitution.

{pad | telnet}

Identifies the incoming or outgoing protocol and controls which parameters are available in the next element of this command.

variable-parameter

A parameter that varies depending upon the protocol selected, either pad or telnet, and its role, either incoming or outgoing. Protocol parameters that modify the incoming or outgoing connection behavior during protocol translation session setup are indicated in Table 41 with an X.

reg-exp-match

A standard Cisco regular expression match specification.

into

Makes the substitution into an available protocol parameter.

reg-exp-write

(Optional) A standard Cisco regular expression write specification that uses information from a match specification.


Defaults

No default behavior or values

Command Modes

Translate ruleset configuration

Command History

Release
Modification

12.3(8)T

This command was introduced.


Usage Guidelines

Up to six substitute specifications can be entered on one command line. The ellipses in the format shown above means multiple substitute statements can be specified in a translation ruleset statement.

When you use the first no form of this command, specify the full set of parameters and expressions in the command to be removed. The second no form must specify the correct substitute command and line number within the translation ruleset template.

This command is used to substitute between protocol parameters using regular expressions to match elements with a test string, and to substitute parameters into another string that can take elements from the matched string.

A substitute ... into statement will perform a regular expression match on any available protocol parameter and, if matched, substitute into any available protocol parameter. The regular expression write specification is optional. If the specification is omitted, the current value of the parameter will be taken as the regular expression write specification. This latter provision is a way of using multiple parameter values to set another parameter value. As an example, two successive substitute statements from a Telnet destination address and destination port into a packet assembler/disassembler (PAD) destination address could be specified using the following statements:

substitute telnet dest-addr ^10\.0\.0\.(.)$ into pad dest-addr 111100\1\\1

substitute telnet dest-addr ^10\.0\.0\.(..)$ into pad dest-addr 111100\1\\1

substitute telnet dest-port ^10(...)$ into pad dest-addr

If these successive substitutions were performed using an incoming Telnet connection from IP address 10.0.0.9/10234, the PAD destination address after the first substitution would be 111009\1, and after the second substitution would be 1111009234.

The following statements construct a switched virtual circuit (SVC) source address from the Telnet source information, starting with the source IP address in the form 172.18.#.##, which allows for a subsequent substitution of one field (notice the use of the backslash to concatenate the substitute and into statements):

substitute telnet source-addr ^172\.18\.(.)\.(..) \

into pad source-addr 98\1\2\\1

You can add in elements extracted from the Telnet destination port, where the rewrite pattern is taken from the current value of PAD source address, as follows:

substitute telnet dest-port ^.(...). into pad source-addr

Table 41 lists the PAD and Telnet parameters that can be set, as indicated by an X.

Table 41 Substitute Connection Parameter Keywords 

Parameter
Description
Incoming PAD
Outgoing Telnet
Outgoing PAD
Incoming Telnet

authorize-method ASCII-string

Connection authorization method to use that must match one of a fixed set of values.

X

X

authorize-tag ASCII-string

Connection authorization identity to supply, entered as an ASCII string.

X

X

binary flag

Flag that specifies whether 8-bit binary data is required, entered as one of the following characters to specify binary mode: Y, y, 1-9,
T
, t.

X

X

cud ASCII-string

Call user data (CUD) that occurs after the protocol identification (PID). For X.29 service, this is the optional, user-specified text included in the command to place a call.

X

X

dest-addr address

Destination IP (Telnet) or X.121 (PAD) address.

X

X

X

X

dest-addr-ext address

Network service access point (NSAP) destination address extension.

X

X

dest-port port

Destination port entered as a decimal number from one to five digits long.

X

X

dlci number

Frame Relay data-link connection identifier (DLCI) of an Annex G service entered as a number from one to seven digits in length, although a size of two to four digits is more likely, or the NULL string if not received on an Annex G service.

X

X

eor specification

A character set defining the End-of-Record (EOR) string for the protocol translation session, entered as an ASCII or hexadecimal specification from one to four bytes in length, aaa or 0x19, as examples.

X

X

eor-insert flag

Flag specifying that the EOR character set should be inserted for PAD data being forwarded to a Telnet session, and entered as a single character. Use one of the following characters to specify EOR insertion: Y, y, 1-9, T, t.

X

X

hostname address

Destination host name for Domain Name System (DNS) resolution entered as an ASCII string.

X

idle seconds

Number of seconds the PAD connection can be idle before being cleared.

X

X

interface type number

Interface to be used for the circuit, entered using standard Cisco IOS interface designations; Serial1/0:1, for example.

X

X

keepalive-period seconds

A number that indicates the number of seconds between TCP keepalives for the X.25 over TCP (XOT) connection.

TCP keepalive information applies only when a ruleset is configured to match an XOT destination address. Example:

match dest-addr ^5555.$ xot-dest-addr 5.5.5.2

X

X

keepalive-tries number

A number that indicates the number of TCP keepalives to send before the XOT connection is declared dead.

TCP keepalive information applies only when a ruleset is configured to match an XOT destination address. Example:

match dest-addr ^5555.$ xot-dest-addr 5.5.5.2

X

X

local flag

Flag specifying that Telnet control sequences should be forwarded, not processed, and entered as a single character. Use one of the following characters to specify local mode: Y, y, 1-9, T, t.

X

X

mac address

Connection-Mode Network Service (CMNS) service remote host MAC address entered as three hexadecimal numbers of four digits separated by a period, (0000.fc08.12ab, for example) or the NULL string if not received on a CMNS service.

X

X

no-reset

Suppress a PVC Reset packet at session startup.

X

X

packetsize size

X.25 maximum data packet sizes to request, entered as two numbers from the following choices: 16, 32, 64, 128, 256, 512, 1024, 2048, 4096.

X

X

pid byte-string

PID string specified in ASCII or hexadecimal. A hexadecimal PID must be prefixed by "0x." For example, 0x01000000 is the standard PAD PID. Although it is available for specifying a nonstandard Call PID, this parameter is not restricted to the common PID length and can be used to specify the entire user data field.

X

X

printer flag

Printer access mode. Flag specifying that the outgoing connection should be brought up before the incoming connection is confirmed. Use one of the following characters to specify printer mode: Y, y, 1-9, T, t.

An unsuccessful outgoing connection attempt results in the incoming connection to the ruleset being refused, rather than being accepted and then closed, which is the default behavior. Note that using this keyword will force the ruleset quiet keyword to be applied to the translation.

X

X

profile name

Named PAD profile to use.

X

X

pvc circuit-number

Permanent virtual circuit (PVC) entered as a number from 1 to 4095, or the null string if not a PVC.

X

reverse

Request reverse charging.

X

reversed flag

Flag to indicate whether a reverse charged Call is permitted. This flag applies to a switched virtual circuit (SVC) and is entered as a single character, Y or N, for yes or no.

X

rotor

Modifies the behavior of the host-name keyword by allowing one of the IP addresses defined by the ip host configuration command to be chosen randomly. If one address fails, another will be tried until a connection is made or all address choices are exhausted.

X

source-addr address

Source X.121 address.

X

X

X

source-addr-ext address

NSAP source address extension.

X

X

source-ifc type number

Interface from which to take the source IP address, entered using standard Cisco IOS interface designations: Loopback0, for example.

X

X

stream flag

Flag that specifies whether Telnet negotiation should be sent or accepted, entered as one of the following characters to specify stream mode: Y, y, 1-9, T, t.

X

X

swap flag

X.29 role reversal. Flag that indicates the PAD connection should not initiate X.29 commands when first connected. Use one of the following characters to swap behavior: Y, y, 1-9, T, t.

This parameter enables incoming and outgoing PAD connections to be swapped so that a protocol translation is treated like a PAD when it accepts a call. By default, the protocol translation functions like a PAD for calls that it initiates, and like an X.25 host for calls it accepts.

X

X

use-map map

Use the map defined for PAD service.

X

windowsize size

X.25 window sizes to request, entered as two numbers in a range from 1 to 127.

X

X

xot-dest-addr address

Destination IP address of an X.25 over TCP (XOT) service entered in standard IP address dotted decimal notation (10.0.0.127, for example) or the NULL string if not received on an XOT service.

X

X

xot-source-addr address

Source IP address of an XOT service entered in standard IP address dotted decimal notation (10.0.0.127, for example) or the NULL string if not received on an XOT service.

X


Examples

The following example shows how to build a translation ruleset template by starting with a match connection test, specifying protocol translation options, and setting specific parameters for incoming Telnet connections. The translation ruleset goes on to test and set appropriate parameters for incoming PAD connections, and to construct an SVC source address from Telnet information starting with the source IP address expressed using regular expression characters that allow for subsequent substitution in its last two fields. The translation ruleset is completed by adding in elements extracted from the Telnet destination port; the rewrite pattern is taken from the current value of PAD source address. Note use of the backslash character to construct the test ... set and substitute ... into statements.

translate ruleset customer-case-1 from telnet to pad
! Match an incoming Telnet attempt destined for IP addresses starting 
! with 172.18., and a 5-digit port starting with the numbers 120 through 127.
 match dest-addr ^172\.18\..* dest-port ^12[0-7]..$
! Once the correct network is matched, specify that this ruleset is limited
! to ten concurrent users and requires a login exchange.
 options max-users 10 login
! Set Telnet options:
 set telnet printer Y telnet binary Y
! Set PAD options:
 set pad profile cust-profile-one
! Test conditional parameters and make appropriate settings:
 test telnet dest-addr ^172\.18\.0\.* telnet dest-port ^10.00 \
   set pad pvc 1 telnet binary T
! Construct an SVC source address from the Telnet source information; 
! start with the source IP address in the form 172.18.#.##, allowing
! for substitutions in the last two fields:
 substitute telnet source-addr ^172\.18\.(.)\.(..)	\ 
   into pad source-addr 98\1\2\\1
! Now add in an extract from the Telnet destination port,
! where the rewrite pattern is taken from the current value of the PAD
! source address:
 substitute telnet dest-port ^.(...). into pad source-addr

Related Commands

Command
Description

description (ruleset)

Adds a description about a translation ruleset.

match (ruleset)

Identifies a connection for processing by the translation ruleset.

options (ruleset)

Specifies protocol translation options in a translation ruleset.

set (ruleset)

Unconditionally sets one or more connection parameters to a fixed value for a translation ruleset.

show translate ruleset

Displays a summary of a specific or of all configured translation rulesets, behavioral parameters, and usage statistic.

skip (ruleset)

Identifies a connection for omission by the translation ruleset.

test (ruleset)

Tests parameter values in a translation ruleset using regular expressions.

test translate

Displays a trace of protocol translation behavior for a connection attempt.

translate ruleset

Defines a unique name for a translation ruleset, specifies translated protocols, and enters translate ruleset configuration mode.

x25 pvc translate ruleset

Configures PVCs that are valid for protocol translation ruleset handling.


telnet

To log in to a host that supports Telnet, use the telnet command in EXEC mode.

telnet host [port] [keyword]

Syntax Description

host

A host name or an IP address.

port

(Optional) A decimal TCP port number; the default is the Telnet router port (decimal 23) on the host.

keyword

(Optional) One of the keywords listed in Table 42.


Command Modes

EXEC

Command History

Release
Modification

10.0

This command was introduced.

12.0(21)ST

The /ipv4 and /ipv6 keywords were added.

12.1

The /quiet keyword was added.

12.2(2)T

Support for the /ipv4 and /ipv6 keywords was integrated into Cisco IOS Release 12.2(2)T.


Usage Guidelines

Table 42 lists the optional telnet command keywords.

Table 42 telnet Keyword Options 

Option
Description

/debug

Enables Telnet debugging mode.

/encrypt kerberos

Enables an encrypted Telnet session. This keyword is available only if you have the Kerberized Telnet subsystem.

If you authenticate using Kerberos Credentials, the use of this keyword initiates an encryption negotiation with the remote server. If the encryption negotiation fails, the Telnet connection will be reset. If the encryption negotiation is successful, the Telnet connection will be established, and the Telnet session will continue in encrypted mode (all Telnet traffic for the session will be encrypted).

/ipv4

Forces the use of IP version 4.

/ipv6

Forces the use of IP version 6.

/line

Enables Telnet line mode. In this mode, the Cisco IOS software sends no data to the host until you press the Enter key. You can edit the line using the standard Cisco IOS software command-editing characters. The /line keyword is a local switch; the remote router is not notified of the mode change.

/noecho

Disables local echo.

/quiet

Prevents onscreen display of all messages from the Cisco IOS software.

/route path

Specifies loose source routing. The path argument is a list of host names or IP addresses that specify network nodes and ends with the final destination.

/source-interface

Specifies the source interface.

/stream

Turns on stream processing, which enables a raw TCP stream with no Telnet control sequences. A stream connection does not process Telnet options and can be appropriate for connections to ports running UNIX-to-UNIX Copy Program (UUCP) and other non-Telnet protocols.

port-number

Port number.

bgp

Border Gateway Protocol.

chargen

Character generator.

cmd rcmd

Remote commands.

daytime

Daytime.

discard

Discard.

domain

Domain Name Service.

echo

Echo.

exec

EXEC.

finger

Finger.

ftp

File Transfer Protocol.

ftp-data

FTP data connections (used infrequently).

gopher

Gopher.

hostname

Host name server.

ident

Ident Protocol.

irc

Internet Relay Chat.

klogin

Kerberos login.

kshell

Kerberos shell.

login

Login (rlogin).

lpd

Printer service.

nntp

Network News Transport Protocol.

node

Connect to a specific LAT node

pop2

Post Office Protocol v2.

pop3

Post Office Protocol v3.

port

Destination LAT port name.

smtp

Simple Mail Transport Protocol.

sunrpc

Sun Remote Procedure Call.

syslog

Syslog.

tacacs

Specify TACACS security.

talk

Talk.

telnet

Telnet.

time

Time.

uucp

UNIX-to-UNIX Copy Program.

whois

Nickname.

www

World Wide Web.


With the Cisco IOS implementation of TCP/IP, you are not required to enter the connect or telnet commands to establish a terminal connection. You can enter only the learned host name—as long as the following conditions are met:

The host name is different from a command word for the router.

The preferred transport protocol is set to telnet.

To display a list of the available hosts, use the show hosts command. To display the status of all TCP connections, use the show tcp command.

The Cisco IOS software assigns a logical name to each connection, and several commands use these names to identify connections. The logical name is the same as the host name, unless that name is already in use, or you change the connection name with the name-connection EXEC command. If the name is already in use, the Cisco IOS software assigns a null name to the connection.

The Telnet software supports special Telnet commands in the form of Telnet sequences that map generic terminal control functions to operating system-specific functions. To issue a special Telnet command, enter the escape sequence and then a command character. The default escape sequence is Ctrl-^ (press and hold the Ctrl-Shift-6). You can enter the command character as you hold down Ctrl or with Ctrl released; you can use either uppercase or lowercase letters. Table 43 lists the special Telnet escape sequences.

Table 43 Special Telnet Escape Sequences

Escape Sequence1
Purpose

Ctrl-^ b

Break

Ctrl-^ c

Interrupt Process (IP)

Ctrl-^ h

Erase Character (EC)

Ctrl-^ o

Abort Output (AO)

Ctrl-^ t

Are You There? (AYT)

Ctrl-^ u

Erase Line (EL)

1 The caret (^) symbol refers to Shift-6 on your keyboard.


At any time during an active Telnet session, you can list the Telnet commands by pressing the escape sequence keys followed by a question mark at the system prompt:

Ctrl-^ ?

A sample of this list follows.

In this sample output, the first caret (^) symbol represents the Ctrl key, and the second caret represents Shift-6 on your keyboard:

Router> ^^?
[Special telnet escape help]
^^B  sends telnet BREAK
^^C  sends telnet IP
^^H  sends telnet EC
^^O  sends telnet AO
^^T  sends telnet AYT
^^U  sends telnet EL 

You can have several concurrent Telnet sessions open and switch between them. To open a subsequent session, first suspend the current connection by pressing the escape sequence (Ctrl-Shift-6 then x [Ctrl^x] by default) to return to the system command prompt. Then open a new connection with the telnet command.

To terminate an active Telnet session, enter any of the following commands at the prompt of the device to which you are connecting:

close

disconnect

exit

logout

quit

Examples

The following example establishes an encrypted Telnet session from a router to a remote host named host1:

Router> telnet host1 /encrypt kerberos

The following example routes packets from the source system host1 to kl.sri.com, then to 10.1.0.11, and finally back to host1:

Router> telnet host1 /route:kl.sri.com 10.1.0.11 host1

The following example connects to a host with logical name host1:

Router> host1

The following example suppresses all onscreen messages from the Cisco IOS software during login and logout:

Router> telnet host2 /quiet

The following example shows the limited number of messages displayed when connection is done using the optional /quiet keyword:

login:User2
Password:
         Welcome to OpenVMS VAX version V6.1 on node CRAW
     Last interactive login on Tuesday, 15-DEC-1998 11:01
     Last non-interactive login on Sunday,  3-JAN-1999 22:32

Server3)logout
    User2        logged out at  16-FEB-2000 09:38:27.85

Related Commands

Command
Description

connect

Logs in to a host that supports Telnet, rlogin, or LAT.

kerberos clients mandatory

Causes the rsh, rcp, rlogin, and telnet commands to fail if they cannot negotiate the Kerberos Protocol with the remote server.

name connection

Assigns a logical name to a connection.

rlogin

Logs in to a UNIX host using rlogin.

show hosts

Displays the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of host names and addresses.

show tcp

Displays the status of TCP connections.


telnet break-on-ip

To cause the system to generate a hardware BREAK signal on the EIA/TIA-232 line that is associated with a reverse Telnet connection when a Telnet Interrupt-Process command is received on that connection, use the telnet break-on-ip command in line configuration mode.

telnet break-on-ip

Syntax Description

This command has no arguments or keywords.

Defaults

No hardware BREAK signal is generated when an Interrupt-Process command is received.

Command Modes

Line configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

This command causes the system to generate a hardware BREAK signal on the EIA/TIA-232 line that is associated with a reverse Telnet connection. It is useful when a Telnet Interrupt-Process command is received on that connection because it can control the translation of Telnet Interrupt-Process commands into X.25 BREAK indications. It is also a useful workaround in the following situations:

Several user Telnet programs send an Interrupt-Process command, but cannot send a Telnet BREAK signal.

Some Telnet programs implement a BREAK signal that sends an Interrupt-Process command.

Some EIA/TIA-232 hardware devices use a hardware BREAK signal for various purposes.

A hardware BREAK signal is generated when a Telnet BREAK command is received.

Examples

In the following example, line 5 is configured with the telnet break-on-ip command. The location text notes that this line is the location of the high-speed modem. The telnet transparent command sets end-of-line handling.

line 5
 location high-speed modem
 telnet transparent
 telnet break-on-ip

Related Commands

Command
Description

connect

Logs in to a host that supports Telnet, rlogin, or LAT.

telnet

Logs in to a host that supports Telnet.

telnet transparent

Configures the Cisco IOS software to send a CARRIAGE RETURN (CR) as a CR followed by a NULL instead of a CR followed by a LINE FEED (LF).

terminal telnet break-on-ip

Causes the access server to generate a hardware Break signal on the EIA/TIA-232 line, which is associated with a reverse Telnet connection, for the current line and sessions.


telnet refuse-negotiations

To set a line using Telnet to refuse to negotiate full-duplex, remote echo requests on incoming connections, use the telnet refuse-negotiations command in line configuration mode. To disable this function, use the no form of this command.

telnet refuse-negotiations

no telnet refuse-negotiations

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values.

Command Modes

Line configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Use this command on reverse Telnet connections to allow the Cisco IOS software to refuse full-duplex, remote echo option connection requests from the other end. This command suppresses negotiation of the Telnet Remote Echo and Suppress Go Ahead options.

This command does not apply to protocol translation configurations. It is intended for applications in which the router is functioning as a terminal server to allow terminal connections to remote devices through the asynchronous terminal ports of the router. Terminal server connections are those where the user types a command similar to the following to access network resources:

telnet access-server 2005

where access-server is the host name of the Cisco router functioning as a terminal server, and 2005 is the port number on the router to which the remote terminal is connected.

Examples

The following example shows how to set line 5 to refuse full-duplex, remote echo requests:

line 5
 telnet refuse-negotiations

Related Commands

Command
Description

connect

Logs in to a host that supports Telnet, rlogin, or LAT.

telnet

Logs in to a host that supports Telnet.

terminal telnet refuse-negotiations

Sets the current line to refuse to negotiate full-duplex, remote echo options on incoming connections for current sessions.


telnet speed

To allow negotiation of the transmission speed of the line to a connected device, use the telnet speed command in line configuration mode. To disable this function, use the no form of this command.

telnet speed default-speed maximum-speed

no telnet speed

Syntax Description

default-speed

Line speed, in bits per second, that the Cisco IOS software will use if the device on the other end of the connection has not specified a speed.

maximum-speed

Maximum speed, in bits per second, that the device on the port will use.


Defaults

No default behavior or values.

Command Modes

Line configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Negotiates speeds on reverse Telnet lines. You can match line speeds on remote systems in reverse Telnet, on host machines hooked up to a router used to access the network, or on a group of console lines hooked up to the router, when disparate line speeds are in use at the local and remote ends of the connection. Line speed negotiation adheres to the Remote Flow Control option defined in RFC 1080.

Examples

The following example allows a router to negotiate a bit rate on the line using the Telnet option. If no speed is negotiated, the line will run at 2400 bits per second (bps). If the remote host requests a speed of greater than 9600 bps, then 9600 will be used.

line 5
 telnet speed 2400 9600

Related Commands

Command
Description

connect

Logs in to a host that supports Telnet, rlogin, or LAT.

telnet

Logs in to a host that supports Telnet.

terminal telnet speed

Allows the access server to negotiate transmission speed for the current line and session.


telnet sync-on-break

To configure the Cisco IOS software to cause an incoming connection to send a Telnet Synchronize signal when it receives a Telnet BREAK signal, use the telnet sync-on-break command in line configuration mode. To disable this function, use the no form of this command.

telnet sync-on-break

no telnet sync-on-break

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values.

Command Modes

Line configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

This command causes a reverse Telnet line to send a Telnet Synchronize signal when it receives a Telnet BREAK signal. This option is used very rarely to ensure the ordering of BREAK reception with respect to data characters sent after the BREAK.

Examples

The following example configures the AUX line with the telnet sync-on-break command:

line aux 0
 telnet sync-on-break

Related Commands

Command
Description

connect

Logs in to a host that supports Telnet, rlogin, or LAT.

telnet

Logs in to a host that supports Telnet.

terminal telnet sync-on-break

Causes the access server to send a Telnet Synchronize signal when it receives a Telnet Break signal on the current line and session.


telnet transparent

To configure the Cisco IOS software to send a CARRIAGE RETURN (CR) as a CR followed by a NULL instead of a CR followed by a LINE FEED (LF), use the telnet transparent command in line configuration mode. To return to the default setting, use the no form of this command.

telnet transparent

no telnet transparent

Syntax Description

This command has no arguments or keywords.

Defaults

CARRIAGE RETURN followed by a LINE FEED.

Command Modes

Line configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

This command is useful for coping with different interpretations of end-of-line handling in the Telnet protocol specification.

Examples

The following example causes the Cisco IOS software, when sending a CR, to send a CR followed by a NULL character:

line 7
 telnet transparent

Related Commands

Command
Description

connect

Logs in to a host that supports Telnet, rlogin, or LAT.

telnet

Logs in to a host that supports Telnet.

terminal telnet transparent

Causes the current terminal line to send a Return character (CR) as a CR followed by a NULL instead of a CR followed by a LINE FEED (LF) for the current session.


terminal lat out-group

To temporarily define the list of services to which you or another user can connect, use the terminal lat out-group command in EXEC mode.

terminal lat out-group group-number [start-end] {disabled | enabled}

Syntax Description

group-number

Number of the group that has access to the system through the specified line. This number is identified by the system administrator. You also can specify a range of group numbers. Separate the beginning and end of the range with a hyphen.

[start-end]

(Optional) You can specify a range of group numbers for the group-number argument. Separate the beginning and end of the range with a hyphen.

disabled

Incrementally removes specified groups from a list.

enabled

Incrementally adds specified groups to a list.


Command Modes

EXEC

Command History

Release
Modification

11.2

This command was introduced.


Usage Guidelines

To temporarily define the list of services to which you or another user can connect, you define the group code lists used for connections from specific lines. You limit the connection choices for an individual line by defining the group code lists for an outgoing connection. When a user initiates a connection with a local-area transport (LAT) host, the line must share a common group number with the remote LAT host before a connection can be made.

The group code range entered in this command must fall within the group code range already configured for the line.

Examples

The following example defines a group code list for the outgoing group 4:

terminal lat out-group 4, 6-189

Related Commands

Command
Description

connect

Logs in to a host that supports Telnet, rlogin, or LAT.

l2f ignore-mid-sequence

Specifies a connection to a particular LAT node that offers LAT services.


terminal lat remote-modification

To set a line running local-area transport (LAT) to be remotely modifiable, use the terminal lat remote-modification command in EXEC mode.

terminal lat remote-modification

Syntax Description

This command has no arguments or keywords.

Command Modes

EXEC

Command History

Release
Modification

11.2

This command was introduced.


Examples

The following example sets line 6 to be remotely modifiable:

terminal lat remote-modification 6

Related Commands

Command
Description

connect

Logs in to a host that supports Telnet, rlogin, or LAT.

l2f ignore-mid-sequence

Specifies a connection to a particular LAT node that offers LAT services.


terminal transport preferred

To specify the preferred protocol to use for the current session when a command does not specify one, use the terminal transport preferred command in EXEC mode.

terminal transport preferred {all | lat | mop | nasi | none | pad | rlogin | telnet | v120}

Syntax Description

all

Specifies all recognized protocols.

lat

Specifies the local-area transport (LAT) protocol.

mop

Specifies the Maintenance Operation Protocol (MOP).

nasi

Specifies the NetWare Asynchronous Services Interface (NASI) protocol.

none

Prevents any protocol selection on the line. The router default is that any unrecognized command is a host name. If the preferred protocol is set to none, the router will not attempt any connections if the command is not recognized.

pad

Specifies X.3 packet assembler/disassembler (PAD), which is used most often to connect a server product to X.25 hosts.

rlogin

Specifies UNIX rlogin.

telnet

Specifies the TCP/IP Telnet protocol.

v120

Selects the V.120 protocol for incoming asynchronous connections over ISDN .


Defaults

lat (if LAT is not supported, telnet)

Command Modes

EXEC

Command History

Release
Modification

10.0

This command first appeared in a release prior to Cisco IOS Release 10.0.

11.2

The following keywords were added:

all

lat

mop

nasi

pad

preferred

rlogin

v120


Examples

The following example configures the console so that it does not connect when an unrecognized command is entered:

terminal transport preferred none

Related Commands

Command
Description

transport preferred

Specifies the transport protocol that the Cisco IOS software uses if the user does not specify one when initiating a connection.


test (ruleset)

To test parameter values in a translation ruleset using regular expressions, use the test command in translate ruleset configuration mode. To change or remove the specification, use one of the two no forms of this command.

test [line-number] {pad | telnet} variable-parameter reg-exp-match [{pad | telnet} variable-parameter reg-exp-match [...]] set {pad | telnet} variable-parameter

no test {pad | telnet} variable-parameter reg-exp-match [{pad | telnet} variable-parameter reg-exp-match [...]] set {pad | telnet} variable-parameter

no test line-number ...

Syntax Description

line-number

(Optional) The line in the translation ruleset to test for substitution.

{pad | telnet}

Identifies the incoming or outgoing protocol and controls which parameters are available in the next element of this command.

variable-parameter

A parameter that varies depending upon the protocol selected, either pad or telnet, and its role, either incoming or outgoing. Protocol parameters are available to modify the incoming or outgoing connection behavior during protocol translation session setup. Up to six parameters can be entered on one command line. Table 44 indicates supported incoming and outgoing PAD and Telnet connection parameter keywords for the test command with an X.

reg-exp-match

A standard Cisco regular expression match specification.

set

Conditionally sets the specified protocol parameters to a fixed value.


Defaults

No default behavior or values

Command Modes

Translate ruleset configuration

Command History

Release
Modification

12.3(8)T

This command was introduced.


Usage Guidelines

Up to six test statements can be entered on one command line. The ellipses in the format shown above means multiple test statements can be specified in a translation ruleset template.

The test command is useful for working with conditional parameters.

A test ... set ... statement conditionally sets one or more connection parameters to a given value, but only after a successful comparison of one or more connection parameters against a regular expression.

When you use the first no form of this command, specify the full set of parameters and expressions in the command to be removed. The second no form must specify the correct test command and line number within the translation ruleset template.

Table 44 Test Connection Parameter Keywords 

Parameter
Description
Incoming PAD
Outgoing Telnet
Outgoing PAD
Incoming Telnet

authorize-method ASCII-string

Connection authorization method to use that must match one of a fixed set of values.

X

X

authorize-tag ASCII-string

Connection authorization identity to supply, entered as an ASCII string.

X

X

binary flag

Flag that specifies whether 8-bit binary data is required, entered as one of the following characters to specify binary mode: Y, y, 1-9,
T
, t.

X

X

cud ASCII-string

Call user data (CUD) that occurs after the protocol identification (PID). For X.29 service, this is the optional, user-specified text included in the command to place a call.

X

X

dest-addr address

Destination IP (Telnet) or X.121 (PAD) address.

X

X

X

X

dest-addr-ext address

Network service access point (NSAP) destination address extension.

X

X

dest-port port

Destination port entered as a decimal number from one to five digits long.

X

dlci number

Frame Relay data-link connection identifier (DLCI) of an Annex G service entered as a number from one to seven digits in length, although a size of two to four digits is more likely, or the NULL string if not received on an Annex G service.

X

X

eor specification

A character set defining the End-of-Record (EOR) string for the protocol translation session, entered as an ASCII or hexadecimal specification from one to four bytes in length, aaa or 0x19, as examples.

X

X

eor-insert flag

Flag specifying that the EOR character set should be inserted for PAD data being forwarded to a Telnet session, and entered as a single character. Use one of the following characters to specify EOR insertion: Y, y, 1-9, T, t.

X

X

hostname address

Destination host name for Domain Name System (DNS) resolution entered as an ASCII string.

X

idle seconds

Number of seconds the PAD connection can be idle before being cleared.

X

X

interface type number

Interface to be used for the circuit, entered using standard Cisco IOS interface designations; Serial1/0:1, for example.

X

X

keepalive-period seconds

A number that indicates the number of seconds between TCP keepalives for the X.25 over TCP (XOT) connection.

TCP keepalive information applies only when a ruleset is configured to match an XOT destination address. Example:

match dest-addr ^5555.$ xot-dest-addr 5.5.5.2

X

X

keepalive-tries number

A number that indicates the number of TCP keepalives to send before the XOT connection is declared dead.

TCP keepalive information applies only when a ruleset is configured to match an XOT destination address. Example:

match dest-addr ^5555.$ xot-dest-addr 5.5.5.2

X

X

local flag

Flag specifying that Telnet control sequences should be forwarded, not processed, and entered as a single character. Use one of the following characters to specify local mode: Y, y, 1-9, T, t.

X

X

mac address

Connection-Mode Network Service (CMNS) service remote host MAC address entered as three hexadecimal numbers of four digits separated by a period, (0000.fc08.12ab, for example) or the NULL string if not received on a CMNS service.

X

X

no-reset

Suppress a PVC Reset packet at session startup.

X

X

packetsize size

X.25 maximum data packet sizes to request, entered as two numbers from the following choices: 16, 32, 64, 128, 256, 512, 1024, 2048, 4096.

X

X

pid byte-string

PID string specified in ASCII or hexadecimal. A hexadecimal PID must be prefixed by "0x." For example, 0x01000000 is the standard PAD PID. Although it is available for specifying a nonstandard Call PID, this parameter is not restricted to the common PID length and can be used to specify the entire user data field.

X

X

printer flag

Printer access mode. Flag specifying that the outgoing connection should be brought up before the incoming connection is confirmed. Use one of the following characters to specify printer mode: Y, y, 1-9, T, t.

An unsuccessful outgoing connection attempt results in the incoming connection to the ruleset being refused, rather than being accepted and then closed, which is the default behavior. Note that using this keyword will force the ruleset quiet keyword to be applied to the translation.

X

X

profile name

Named PAD profile to use.

X

X

pvc circuit-number

Permanent virtual circuit (PVC) entered as a number from 1 to 4095, or the null string if not a PVC.

X

reverse

Request reverse charging.

X

reversed flag

Flag to indicate whether a reverse charged Call is permitted. This flag applies to a switched virtual circuit (SVC) and is entered as a single character, Y or N, for yes or no.

X

rotor

Modifies the behavior of the host-name keyword by allowing one of the IP addresses defined by the ip host configuration command to be chosen randomly. If one address fails, another will be tried until a connection is made or all address choices are exhausted.

X

source-addr address

Source X.121 address.

X

X

X

source-addr-ext address

NSAP source address extension.

X

X

source-ifc type number

Interface from which to take the source IP address, entered using standard Cisco IOS interface designations: Loopback0, for example.

X

X

stream flag

Flag that specifies whether Telnet negotiation should be sent or accepted, entered as one of the following characters to specify stream mode: Y, y, 1-9, T, t.

X

X

swap flag

X.29 role reversal. Flag that indicates the PAD connection should not initiate X.29 commands when first connected. Use one of the following characters to swap behavior: Y, y, 1-9, T, t.

This parameter enables incoming and outgoing PAD connections to be swapped so that a protocol translation is treated like a PAD when it accepts a call. By default, the protocol translation functions like a PAD for calls that it initiates, and like an X.25 host for calls it accepts.

X

X

use-map map

Use the map defined for PAD service.

X

windowsize size

X.25 window sizes to request, entered as two numbers in a range from 1 to 127.

X

X

xot-dest-addr address

Destination IP address of an X.25 over TCP (XOT) service entered in standard IP address dotted decimal notation (10.0.0.127, for example) or the NULL string if not received on an XOT service.

X

X

xot-source-addr address

Source IP address of an XOT service entered in standard IP address dotted decimal notation (10.0.0.127, for example) or the NULL string if not received on an XOT service.

X


Examples

The following example shows how to integrate a test into a translation ruleset template. The translation ruleset begins with the required match connection test, specifies protocol translation options, and sets specific parameters for incoming Telnet connections. The translation ruleset goes on to test and set appropriate parameters for incoming PAD connections, and to construct an SVC source address from Telnet information, starting with the source IP address. The translation ruleset is completed by adding in elements extracted from the Telnet destination port; the rewrite pattern is taken from the current value of PAD source address. The backslash character is used to construct the test ... set and substitute ... into statements.

translate ruleset customer-case-1 from telnet to pad
! Match an incoming Telnet attempt destined for IP addresses starting 
! with 172.18., and a 5-digit port starting with the numbers 120 through 127.
 match dest-addr ^172\.18\..* dest-port ^12[0-7]..$
! Once the correct network is matched, specify that this ruleset is limited
! to ten concurrent users and requires a login exchange.
 options max-users 10 login
! Set Telnet options:
 set telnet printer Y telnet binary Y
! Set PAD options:
 set pad profile cust-profile-one
! Test conditional parameters and make appropriate settings:
 test telnet dest-addr ^172\.18\.0\.* telnet dest-port ^10.00 \
   set pad pvc 1 telnet binary T
! Construct an SVC source address from the Telnet source information; 
! start with the source IP address in the form 172.18.#.##, allowing
! for a following substitute of one field:
 substitute telnet source-addr ^172\.18\.(.)\.(..)	\ 
   into pad source-addr 98\1\2\\1
! Now add in an extract from the Telnet destination port,
! where the rewrite pattern is taken from the current value of the PAD
! source address:
 substitute telnet dest-port ^.(...). into pad source-addr

Related Commands

Command
Description

description (ruleset)

Adds a description about a translation ruleset.

match (ruleset)

Identifies a connection for processing by the translation ruleset.

options (ruleset)

Specifies protocol translation options in a translation ruleset.

set (ruleset)

Unconditionally sets one or more connection parameters to a fixed value for a translation ruleset.

show translate ruleset

Displays a summary of a specific or of all configured translation rulesets, behavioral parameters, and usage statistic.

skip (ruleset)

Identifies a connection for omission by the translation ruleset.

substitute (ruleset)

Matches an available protocol and substitutes another in a translation ruleset.

test translate

Displays a trace of protocol translation behavior for a connection attempt.

translate ruleset

Defines a unique name for a translation ruleset, specifies translated protocols, and enters translate ruleset configuration mode.

x25 pvc translate ruleset

Configures PVCs that are valid for protocol translation ruleset handling.


test translate

To display a trace of protocol translation behavior for a connection attempt, use the test translate command in user or privileged EXEC mode.

test translate {pad | telnet | parameter parameter} [detail]

Syntax Description

pad

Tests a trace of a packet assembler/disassembler (PAD) connection attempt.

telnet

Tests a trace of a Telnet connection attempt.

parameter parameter

Tests one of the following translation ruleset parameters in interactive mode:

boolean—Boolean expression parameter. True if at least one character is present and the first character is one of Y, y, 1-9, T, or t; otherwise, false.

hexstring—Hex string parameter. A standard hexadecimal string representation starting with 0x, such as 0x14000F0000.

integer—Integer parameter. A standard decimal number from 0 to 65535.

interface—Two-integer parameter. A character string, possibly with embedded white space, identifying an existing interface, such as Serial 1, on the router.

ip—IP address parameter. A standard four-byte dotted decimal IP address such as 10.0.0.127.

mac—MAC address parameter. A standard set of three 4-digit hexadecimal words in dotted MAC address form such as 0001.00a8.1f2c.

nsap—Network service access point (NSAP) address parameter.

string—String parameter. A null-terminated ASCII string.

two-integer—Two-integer parameter.

x121—X.121 address parameter. A standard X.121 address from 1 to 15 decimal digits long.

detail

(Optional) Provides a more detailed test report.


Defaults

No default behavior or values

Command Modes

User EXEC
Privileged EXEC

Command History

Release
Modification

12.3(8)T

This command was introduced.


Usage Guidelines

This command will traverse the set of protocol translation configurations in the order they are listed in the translation ruleset, and report all events that take place. The detail keyword shows each line being evaluated and detailed translation test information.

The translation ruleset operations to test, set, and substitute protocol parameter values use strings, and the ruleset generates the set of protocol parameter values as a set of strings. When entered with the optional parameter keyword and parameter type, the test translate command becomes interactive and queries for incoming connection parameter values. For a given protocol parameter there may be additional validation tests that apply. If the application of a translation ruleset results in an invalid value for a parameter (whether a violation of the basic type rule or the more specific validation tests for the parameter), the protocol translation operation will fail with an informative message.

Configuration errors are not detected when translation ruleset commands are entered. They are tested when the connection is attempted or when you use the test (ruleset) command. In the following example, the set translation ruleset command unconditionally sets the PAD's profile name to a profile that does not exist in the configuration:

set pad profile Bldg-1-5ess

This command would be accepted at the command-line interpreter, but not tested until a connection attempt or with the test translate EXEC command. When the error is detected, the following messages display:

*%PT-3-PARAMRESULTERR: PT ruleset test protocol pad parameter profile parse error: Bldg-1-5ess.

-Process= "PAD InCall", ipl= 3, pid= 94

*PAD: ruleset translation not generated Cause: 9 Diag: 0

Examples

The following example shows a sample of the self-explanatory report from the test translate command:

Router# test translate pad

  dest-addr (X.121 address): 55555 
Ruleset A match/skip line 1 compared: match 
Ruleset A; pad parameter read: 
  pad/dest-addr: 55555 
Parameters set: 
  telnet/dest-addr: 10.2.2.1

Translate From: PAD 55555 
          To:   Telnet 10.2.2.1 Port 23 
          Ruleset A 
          0/1 users active 

The following is a sample of a detailed report:

Router# test translate pad detail

PAD translate command 1 PVC match not required 
  dest-addr (X.121 address): 55555 
  Normalized PAD dest-addr: 55555 
PAD translate command 1 skipped, destination address 55555 doesn't match 12345 
PAD translate command 2 PVC match not required 
PAD translate command 2 skipped, destination address 55555 doesn't match 55551 
No PAD translate command matched 
(Testing translate command A ...) 
Ruleset A match/skip line 1 compared: match 
  (processing set/test/substitute line 1) 
  (set/test/subst line 1, item 1, parameter dest-addr set to 10.2.2.1) 
  (parsed telnet parameter dest-addr: 10.2.2.1) 
Ruleset A; pad parameter read: 
  pad/dest-addr: 55555 
Parameters set: 
  telnet/dest-addr: 10.2.2.1 
  (translation requires 0 bytes variable-sized memory)

Translate From: PAD 55555 
          To:   Telnet 10.2.2.1 Port 23 
          Ruleset A 
          0/1 users active 

The following example tests the boolean translate ruleset parameter in interactive mode:

Router# test translate parameter boolean

  Enter parameter value (boolean): Y

  Enter encode buffer size (integer): 10
Encoded into Y
Router# 

Related Commands

Command
Description

description (ruleset)

Adds a description about a translation ruleset.

match (ruleset)

Identifies a connection for processing by the translation ruleset.

options (ruleset)

Specifies protocol translation options in a translation ruleset.

set (ruleset)

Unconditionally sets one or more connection parameters to a fixed value for a translation ruleset.

show translate ruleset

Displays a summary of a specific or of all configured translation rulesets, behavioral parameters, and usage statistic.

skip (ruleset)

Identifies a connection for omission by the translation ruleset.

substitute (ruleset)

Matches an available protocol and substitutes another in a translation ruleset.

test (ruleset)

Tests parameter values in a translation ruleset using regular expressions.

translate ruleset

Defines a unique name for a translation ruleset, specifies translated protocols, and enters translate ruleset configuration mode.

x25 pvc translate ruleset

Configures PVCs that are valid for protocol translation ruleset handling.


tn3270

To begin a TN3270 session, use the tn3270 command in EXEC mode.

tn3270 host

Syntax Description

host

Name or IP address of a specific host on a network that can be reached by the router. The default terminal emulation mode allows access using a VT100 emulation.


Command Modes

EXEC

Command History

Release
Modification

11.1

This command was introduced.


Usage Guidelines

Unlike Telnet and local-area transport (LAT) connections, you must enter the tn3270 command to make a connection to an IBM TN3278 host.

To terminate an active TN3270 session, enter the escape sequence (Ctrl-Shift-6 then x [Ctrl^x] by default) and enter the disconnect command at the EXEC prompt. Or log off the remote system by issuing the command specific to that system (such as exit, logout, quit, close, or disconnect).

Examples

The following example establishes a terminal session with an IBM TN3270 host named finance:

tn3270 finance

tn3270 8bit display

To configure the Cisco IOS software to use the mask set by the data-character-bits {7 | 8} command in line configuration mode or the terminal data-character bits {7 | 8} EXEC command, use the tn3270 8bit display command in line configuration mode. To restore the default 7-bit mask used for TN3270 connections, use the no form of this command.

tn3270 8bit display

no tn3270 8bit display

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

Line configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Use the tn3270-character-map command to map between extended EBCDIC or extended ASCII characters.

Examples

The following example configures the Cisco IOS software to use the mask set by the data-character-bits line configuration and EXEC commands on line 5:

line 5
 tn3270 8bit display

Related Commands

Command
Description

data-character-bits

Sets the number of data bits per character that are interpreted and generated by the Cisco IOS software.

terminal data-character-bits

Sets the number of data bits per character that are interpreted and generated by the Cisco IOS software for the current line and session.


tn3270 8bit transparent-mode

To configure the Cisco IOS software to use the mask set by the data-character-bits {7 | 8} command in line configuration mode or the terminal data-character bits {7 | 8} EXEC command, use the tn3270 8bit transparent-mode command in line configuration mode. To restore the default 7-bit mask used for TN3270 connections, use the no form of this command.

tn3270 8bit transparent-mode

no tn3270 8bit transparent-mode

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

Line configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

This command is needed if you are using a file transfer protocol such as Kermit in 8-bit mode or you are using 8-bit graphics, both of which rely on transparent mode.

Examples

The following example configures the software to use the mask set by the data-character-bits line configuration and EXEC commands on line 5:

line 5
 tn3270 8bit transparent-mode

Related Commands

Command
Description

data-character-bits

Sets the number of data bits per character that are interpreted and generated by the Cisco IOS software.

terminal data-character-bits

Sets the number of data bits per character that are interpreted and generated by the Cisco IOS software for the current line and session.


tn3270 character-map

To convert incoming EBCDIC characters into ASCII characters, use the tn3270 character-map command in global configuration mode. To restore default character mappings, use the no form of this command.

tn3270 character-map ebcdic-in-hex ascii-in-hex

no tn3270 character-map {all | ebcdic-in-hex} [ascii-in-hex]

Syntax Description

ebcdic-in-hex

Hexadecimal value of an EBCDIC character.

ascii-in-hex

Hexadecimal value of an ASCII character.

all

Indicates all character mappings.


Defaults

Disabled

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Use this command to print international characters that are EBCDIC characters not normally printed, including umlauts (ยจ) and tildes (~). The command first restores default mapping for both EBCDIC and ASCII characters. In the no form of the command, the all keyword resets all character mappings to Cisco defaults.

Table 45 shows the default character mappings between ASCII and EBCDIC in decimal and hexadecimal format.

To convert outgoing ASCII characters into EBCDIC characters, use the keymap command to modify the keymap structure with the tag ebcdic_xx=string, where xx is a hexadecimal value and string is the sequence of characters that send the EBCDIC character.

Table 45 Default ASCII, EBCDIC Character Mappings 

Character
ASCII Decimal
ASCII Hexadecimal
EBCDIC Decimal
EBCDIC Hexadecimal

!

33

0x21

90

0x5a

"

34

0x22

127

0x7f

#

35

0x23

123

0x7b

$

36

0x24

91

0x5b

%

37

0x25

108

0x6c

&

38

0x26

80

0x50

'

39

0x27

125

0x7d

(

40

0x28

77

0x4d

)

41

0x29

93

0x5d

*

42

0x2a

92

0x5c

+

43

0x2b

78

0x4e

,

44

0x2c

107

0x6b

-

45

0x2d

96

0x60

.

46

0x2e

75

0x4b

/

47

0x2f

97

0x61

0

48

0x30

240

0xf0

1

49

0x31

241

0xf1

2

50

0x32

242

0xf2

3

51

0x33

243

0xf3

4

52

0x34

244

0xf4

5

53

0x35

245

0xf5

6

54

0x36

246

0xf6

7

55

0x37

247

0xf7

8

56

0x38

248

0xf8

9

57

0x39

249

0xf9

:

58

0x3a

122

0x7a

;

59

0x3b

94

0x5e

<

60

0x3c

76

0x4c

=

61

0x3d

126

0x7e

>

62

0x3e

110

0x6e

?

63

0x3f

111

0x6f

@

64

0x40

124

0x7c

A

65

0x41

193

0xc1

B

66

0x42

194

0xc2

C

67

0x43

195

0xc3

D

68

0x44

196

0xc4

E

69

0x45

197

0xc5

F

70

0x46

198

0xc6

G

71

0x47

199

0xc7

H

72

0x48

200

0xc8

I

73

0x49

201

0xc9

J

74

0x4a

209

0xd1

K

75

0x4b

210

0xd2

L

76

0x4c

211

0xd3

M

77

0x4d

212

0xd4

N

78

0x4e

213

0xd5

O

79

0x4f

214

0xd6

P

80

0x50

215

0xd7

Q

81

0x51

216

0xd8

R

82

0x52

217

0xd9

S

83

0x53

226

0xe2

T

84

0x54

227

0xe3

U

85

0x55

228

0xe4

V

86

0x56

229

0xe5

W

87

0x57

230

0xe6

X

88

0x58

231

0xe7

Y

89

0x59

232

0xe8

Z

90

0x5a

233

0xe9

[

91

0x5b

173

0xad

\

92

0x5c

224

0xe0

]

93

0x5d

189

0xbd

^

94

0x5e

95

0x5f

_

95

0x5f

109

0x6d

`

96

0x60

121

0x79

a

97

0x61

129

0x81

b

98

0x62

130

0x82

c

99

0x63

131

0x83

d

100

0x64

132

0x84

e

101

0x65

133

0x85

f

102

0x66

134

0x86

g

103

0x67

135

0x87

h

104

0x68

136

0x88

i

105

0x69

137

0x89

j

106

0x6a

145

0x91

k

107

0x6b

146

0x92

l

108

0x6c

147

0x93

m

109

0x6d

148

0x94

n

110

0x6e

149

0x95

o

111

0x6f

150

0x96

p

112

0x70

151

0x97

q

113

0x71

152

0x98

r

114

0x72

153

0x99

s

115

0x73

162

0xa2

t

116

0x74

163

0xa3

u

117

0x75

164

0xa4

v

118

0x76

165

0xa5

w

119

0x77

166

0xa6

x

120

0x78

167

0xa7

y

121

0x79

168

0xa8

z

122

0x7a

169

0xa9

{

123

0x7b

192

0xc0

|

124

0x7c

79

0x4f

}

125

0x7d

208

0xd0

~

126

0x7e

161

0xa1


Examples

The following example creates a two-way binding between an EBCDIC character and an ASCII character:

tn3270 character-map 0x81 0x78

Related Commands

Command
Description

show tn3270 ascii-hexval

Displays ASCII-hexadecimal character mappings.

show tn3270 character-map

Displays character mappings between ASCII and EBCDIC.


tn3270 datastream

To enable the TN3270 extended datastream, use the tn3270 datastream command in global configuration mode. To return to the normal TN3270 datastream, use the no form of this command.

tn3270 datastream {extended | normal}

no tn3270 datastream

Syntax Description

extended

Extended datastream.

normal

Normal datastream.


Defaults

Normal datastream

Command Modes

Global configuration

Command History

Release
Modification

10.3

This command was introduced.


Usage Guidelines

This command causes an "-E" to be appended to the terminal type string sent to the IBM host, which allows you to use the extended TN3270 features.

Examples

The following example shows the supported TN3270 datastream options:

tn3270 datastream ?
 extended  Use extended TN3270 datastream
 normal    Use normal TN3270 datastream

tn3270 null-processing

To specify how NULL signals are handled, use the tn3270 null-processing command in global configuration mode. To return to 7171 NULL processing, use the no form of this command.

tn3270 null-processing [3270 | 7171]

no tn3270 null-processing [3270 | 7171]

Syntax Description

3270

(Optional) NULLs are compressed out of the string, as on a 3278-x terminal.

7171

(Optional) NULLs are converted to spaces, as on a 7171 controller.


Defaults

7171 NULL processing

Command Modes

Global configuration

Command History

Release
Modification

10.3

This command was introduced.


Usage Guidelines

If a user enters data, uses an arrow key to move the cursor to the right on the screen, and then enters more data, the intervening spaces are filled with NULLs. To specify how NULLs are handled, enter the tn3270 null-processing command either with the 3270 argument, where NULLs are compressed out of the string (as on a real 3278-x terminal) or the 7171 argument, where NULLs are converted to spaces as on a 7171 controller. Enter this command in global configuration.

Examples

The following example shows the two available null processing methods:

tn3270 null-processing ?
 3270  Use 3270-style null processing
 7171  Use 7171-style null processing

tn3270 optimize-cursor-move

To increase performance between a remote user and a TN3270 host by limiting cursor movement information that is sent to user terminals, use the tn3270 optimize-cursor-move command in global configuration mode. To ensure that all cursor movement information is sent between the terminal and the TN3270 host, use the no form of this command.

tn3270 optimize-cursor-move

no tn3270 optimize-cursor-move

Syntax Description

This command has no arguments or keywords.

Defaults

Cursor movement escape strings are sent to the terminal.

Command Modes

Global configuration

Command History

Release
Modification

11.2

This command was introduced.


Usage Guidelines

Issuing this command increases the speed of information transfer between users and TN3270 hosts through an access server.

If you do not issue this command, virtually every byte of information between the terminal and the TN3270 host is prepended and trailed by cursor-movement strings.

Examples

The following example disables status messages to users connected to 3278 terminals:

tn3270 optimize-cursor-move 

Related Commands

Command
Description

tn3270 status-message

Reenables the display of status messages after they have been disabled.


tn3270 reset-required

To lock a terminal after input error until the user resets the terminal, use the tn3270 reset-required command in global configuration mode. To return to the default of no reset required, use the no form of this command.

tn3270 reset-required

no tn3270 reset-required

Syntax Description

This command has no arguments or keywords.

Defaults

No reset is required.

Command Modes

Global configuration

Command History

Release
Modification

10.3

This command was introduced.


Usage Guidelines

On a 3278-x terminal, the keyboard is locked and further input is not permitted after input error (due to field overflow, invalid entry, and so on) until the user presses the RESET key. Most TN3270 implementations leave the keyboard unlocked and remove any error message on the next key input after the error. Use this command to lock the keyboard until the user performs a reset.

Examples

The following example enables keyboard locking after an input error:

tn3270 reset-required

tn3270 status-message

To reenable the display of status messages after they have been disabled, use the tn3270 status-message command in global configuration mode. To save bandwidth on asynchronous lines by not displaying status messages, use the no form of this command.

tn3270 status-message

no tn3270 status-message

Syntax Description

This command has no arguments or keywords.

Defaults

Status messages appear.

Command Modes

Global configuration

Command History

Release
Modification

11.2

This command was introduced.


Usage Guidelines

Status messages appear on the console by default. These messages include "System Locked," "Field error," and "System UnLocked" messages. These messages are sent back to the terminal via the TTY line on the access server.

Disabling status messages saves bandwidth on asynchronous lines, which have very low bandwidth.

Examples

The following example disables status messages to users connected to 3270 terminals:

no tn3270 status-message

Related Commands

Command
Description

tn3270 optimize-cursor-move

Increases performance between a remote user and a TN3270 host by limiting cursor movement information that is sent to user terminals.


tn3270 typeahead

To buffer keyboard data when a 3278 server is in locked mode, use the tn3270 typeahead command in global configuration mode. To disable the typeahead function, use the no form of this command.

tn3270 typeahead

no tn3270 typeahead

Syntax Description

This command has no arguments or keywords.

Defaults

Typeahead is disabled.

Command Modes

Global configuration

Command History

Release
Modification

11.2

This command was introduced.


Usage Guidelines

When typeahead is enabled, the TN3270 client implementation in the Cisco IOS software permits you to continue typing while the system is trying to obtain a response from the TN3270 server. Information you type while a "System Locked" message appears on the terminal is stored in a buffer. After the "System Locked" message disappears, the information is then used as though it were just typed.

Examples

The following example saves user information when "System Locked" messages appear on the screen:

tn3270 typeahead

Related Commands

Command
Description

tn3270 reset-required

Locks a terminal after input error until the user resets the terminal.