Cisco IOS Dial Services Commands: SL Through TN

This chapter explains the function and syntax of the Cisco IOS dial services commands from Sl through TN. For more information about defaults and usage guidelines, see the corresponding chapter of the Cisco IOS Dial Services Command Reference, Release 12.1.

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.

/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.

snapshot client

To configure a client router for snapshot routing, use the snapshot client command in interface configuration mode. Use the no form of this command to disable a client router.

snapshot client active-time quiet-time [suppress-statechange-updates] [dialer]

no snapshot client active-time quiet-time [suppress-statechange-updates] [dialer]

Syntax Description

active-time

Amount of time, in minutes, that routing updates are regularly exchanged between the client and server routers. This can be an integer in the range 5 to 100. There is no default value. A typical value is 5 minutes.

quiet-time

Amount of time, in minutes, that routing entries are frozen and remain unchanged between active periods. Routes are not aged during the quiet period, so they remain in the routing table as if they were static entries. This argument can be an integer from 8 to 100000. There is no default value. The minimum quiet time is generally the active time plus 3.

suppress-statechange-updates

(Optional) Disables the exchange of routing updates each time the line protocol goes from "down" to "up" or from "dialer spoofing" to "fully up."

dialer

(Optional) Used if the client router has to dial up the remote router in the absence of regular traffic.

active-time	Amount of time, in minutes, that routing updates are regularly exchanged between the client and server routers. This can be an integer in the range 5 to 100. There is no default value. A typical value is 5 minutes.
quiet-time	Amount of time, in minutes, that routing entries are frozen and remain unchanged between active periods. Routes are not aged during the quiet period, so they remain in the routing table as if they were static entries. This argument can be an integer from 8 to 100000. There is no default value. The minimum quiet time is generally the active time plus 3.
suppress-statechange-updates	(Optional) Disables the exchange of routing updates each time the line protocol goes from "down" to "up" or from "dialer spoofing" to "fully up."
dialer	(Optional) Used if the client router has to dial up the remote router in the absence of regular traffic.

snapshot server

To configure a server router for snapshot routing, use the snapshot server command in interface configuration mode. Use the no form of this command to disable a server router.

snapshot server active-time [dialer]

no snapshot server active-time [dialer]

active-time	Amount of time, in minutes, that routing updates are regularly exchanged between the client and server routers. This can be an integer in the range 5 to 100. There is no default value. A typical value is 5 minutes.
dialer	(Optional) Allows the client router to dial up the remote router in the absence of regular traffic.

source template

To attach a configured customer profile template to a particular customer profile, use the source template command in customer profile configuration mode.

source template name

Syntax Description

name

Customer profile template name.

name	Customer profile template name.

source-ip

To specify an alternate IP address for a Virtual Private Dialup Network (VPDN) tunnel that is different from the physical IP address used to open the tunnel, use the source-ip command in VPDN group configuration mode. To remove the alternate IP address, use the no form of this command.

source-ip ip-address

no source-ip

Syntax Description

ip-address

Alternate IP address (different from the physical IP address used to open the VPDN tunnel) that the router uses to identify the tunnel.

ip-address	Alternate IP address (different from the physical IP address used to open the VPDN tunnel) that the router uses to identify the tunnel.

spe

To access the SPE configuration mode and control the downloading of firmware into the modems, use the spe command in global configuration mode. There is no no version of this command.

spe {shelf/slot/module} {shelf/slot/module}

Syntax Description

shelf/slot/module

Enter the shelf number, slot number, and module number separated by slashes, as shown. For Cisco AS5200 and AS5300, enter only the slot/module.

To specify a range of modems when this option is selected as a start point, use the following set of arguments as an endpoint.

shelf/slot/module	Enter the shelf number, slot number, and module number separated by slashes, as shown. For Cisco AS5200 and AS5300, enter only the slot/module. To specify a range of modems when this option is selected as a start point, use the following set of arguments as an endpoint.

start-character

To set the flow control start character, use the start-character command in line configuration mode. Use the no form of this command to remove the character.

start-character ascii-number

no start-character

Syntax Description

ascii-number

Decimal representation of the start character.

ascii-number	Decimal representation of the start character.

start-chat

To specify that a chat script start on a specified line at any point, use the start-chat command in privileged EXEC mode. Use the no form of this command to stop the chat script.

start-chat regexp [line-number [dialer-string]]

no start-chat

Syntax Description

regexp

Specifies the name of a regular expression or modem script to be executed. If there is more than one script with a name that matches the argument regexp, the first script found will be used.

line-number

(Optional) Indicates the line number on which to execute the chat script. If you do not specify a line number, the current line number is chosen. If the specified line is busy, the script is not executed and an error message appears. If the dialer-string argument is specified, line-number must be entered; it is not optional if you specify a dialer string. This command functions only on physical terminal (TTY) lines. It does not function on virtual terminal (VTY) lines.

dialer-string

(Optional) String of characters (often a telephone number) to be sent to a DCE. If you enter a dialer string, you must also specify line-number, or the chat script regexp will not start.

regexp	Specifies the name of a regular expression or modem script to be executed. If there is more than one script with a name that matches the argument regexp, the first script found will be used.
line-number	(Optional) Indicates the line number on which to execute the chat script. If you do not specify a line number, the current line number is chosen. If the specified line is busy, the script is not executed and an error message appears. If the dialer-string argument is specified, line-number must be entered; it is not optional if you specify a dialer string. This command functions only on physical terminal (TTY) lines. It does not function on virtual terminal (VTY) lines.
dialer-string	(Optional) String of characters (often a telephone number) to be sent to a DCE. If you enter a dialer string, you must also specify line-number, or the chat script regexp will not start.

stop-character

To set the flow control stop character, use the stop-character command in line configuration mode. Use the no form of this command to remove the character.

stop-character ascii-number

no stop-character

Syntax Description

ascii-number

Decimal representation of the stop character.

ascii-number	Decimal representation of the stop character.

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 options listed in Table 16.

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 options listed in Table 16.

Table 16: telnet Connection 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).

/line

Enables Telnet line mode. In this mode, the Cisco IOS software sends no data to the host until you press Return. 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.

/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 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

NIC hostname 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 (HTTP).

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).
/line	Enables Telnet line mode. In this mode, the Cisco IOS software sends no data to the host until you press Return. 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.
/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 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	NIC hostname 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 (HTTP).

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.

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.

telnet refuse-negotiations

Syntax Description

This command has no arguments or keywords.

telnet speed

To allow the Cisco IOS software to negotiate transmission speed of the line to a connected device, use the telnet speed command in line configuration mode.

telnet speed default-speed maximum-speed

Syntax Description

default-speed

Line speed (in bps) 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 bps) that the device on the port will use.

default-speed	Line speed (in bps) 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 bps) that the device on the port will use.

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.

telnet sync-on-break

Syntax Description

This command has no arguments or keywords.

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.

telnet transparent

Syntax Description

This command has no arguments or keywords.

template

To access the template configuration mode for configuring a particular customer profile template, use the template command in global configuration mode. Use the no form of this command to delete the template of the specified name.

template name {default | exit | multilink | no | peer | ppp}

no template name {default | exit | multilink | no | peer | ppp}

Syntax Description

name

A name that identifies the template.

default

Sets the command to its defaults.

exit

Exits from resource-manager configuration mode.

multilink

Configures multilink parameters.

no

Negates the command or its defaults.

peer

Accesses peer parameters for point-to-point interfaces.

ppp

Accesses Point-to-Point Protocol.

name	A name that identifies the template.
default	Sets the command to its defaults.
exit	Exits from resource-manager configuration mode.
multilink	Configures multilink parameters.
no	Negates the command or its defaults.
peer	Accesses peer parameters for point-to-point interfaces.
ppp	Accesses Point-to-Point Protocol.

terminal lat

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

terminal lat remote-modification

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

Syntax Description

remote-modification

Sets the line to be remotely modifiable.

out-group

Defines a group list for outgoing user-initiated connections.

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 also can specify a range of group numbers with the group_number. Separate the beginning and end of the range with a hyphen.

disabled

Incrementally removes specified groups from list.

enabled

Incrementally adds specified groups to list.

remote-modification	Sets the line to be remotely modifiable.
out-group	Defines a group list for outgoing user-initiated connections.
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 also can specify a range of group numbers with the group_number. Separate the beginning and end of the range with a hyphen.
disabled	Incrementally removes specified groups from list.
enabled	Incrementally adds specified groups to list.

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 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 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 async over ISDN connections.

all	Specifies all recognized protocols.
lat	Specifies the 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 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 async over ISDN connections.

terminate-from

To specify the host name of the remote L2TP access concentrator (LAC) or L2TP network server (LNS) that will be required when accepting a Virtual Private Dialup Network (VPDN) tunnel, use the terminate-from command in VPDN group configuration mode. To remove the host name from the VPDN group, use the no form of this command.

terminate-from hostname hostname

no terminate-from [hostname hostname]

Syntax Description

hostname hostname

(Optional) The host name that this VPDN group will accept connections from.

hostname hostname	(Optional) The host name that this VPDN group will accept connections from.

test modem back-to-back

To diagnose an integrated modem that may not be functioning properly, use the test modem back-to-back command in EXEC mode.

test modem back-to-back first-slot/port second-slot/port

Syntax Description

first-slot/port

Slot and modem number of the first test modem. Remember to include the forward slash (/) when entering this variable.

second-slot/port

Slot and modem number of the second test modem. Remember to include the forward slash (/) when entering this variable.

first-slot/port	Slot and modem number of the first test modem. Remember to include the forward slash (/) when entering this variable.
second-slot/port	Slot and modem number of the second test modem. Remember to include the forward slash (/) when entering this variable.

timer

To set the Redundant Link Manager (RLM) timer, use the timer command in RLM configuration mode. The associated options can overwrite the default setting of timeout values. Use the no form of this command to disable this function.

timer { force-down | keepalive | minimum-up | open-wait | recovery | retransmit | switch-link} time in seconds

Syntax Description

force-down

After RLM enters the down state, RLM will stay in the down state for a certain amount of time to make sure that the remote end will also enter the down state. After this occurs, both can be forced to be in sync again. This timer can also prevent RLM links from going up and down rapidly in an unstable network environment.

keepalive

A keepalive packet will be sent out from Network Access Server (NAS) to CSC periodically.

minimum-up

After a link is recovered from the failure state and RLM is in the up state, RLM will wait for a minimum time to make sure the new recovered link is stabilized before doing any operation.

open-wait

To overcome the latency while opening several links at the same time, RLM will use this timer to wait before opening the new links, and then choose the link with the highest weighting to become the active signaling link.

recovery

When Network Access Server (NAS) loses the active connection to CSC, it will try to reestablish the connection within the interval specified by this command. If it fails to reestablish the connection, RLM will declare that the RLM signaling link is down.

retransmit

Because RLM is operating under UDP, it needs to retransmit the control packet if the packet is not acknowledged within this retransmit interval.

switch-link

The maximum transition period allows RLM to switch from a lower preference link to a higher preference link. If the switching link does not complete successfully before this timer expires, RLM will go into the recovery state.

force-down	After RLM enters the down state, RLM will stay in the down state for a certain amount of time to make sure that the remote end will also enter the down state. After this occurs, both can be forced to be in sync again. This timer can also prevent RLM links from going up and down rapidly in an unstable network environment.

keepalive	A keepalive packet will be sent out from Network Access Server (NAS) to CSC periodically.

minimum-up	After a link is recovered from the failure state and RLM is in the up state, RLM will wait for a minimum time to make sure the new recovered link is stabilized before doing any operation.

open-wait	To overcome the latency while opening several links at the same time, RLM will use this timer to wait before opening the new links, and then choose the link with the highest weighting to become the active signaling link.

recovery	When Network Access Server (NAS) loses the active connection to CSC, it will try to reestablish the connection within the interval specified by this command. If it fails to reestablish the connection, RLM will declare that the RLM signaling link is down.

retransmit	Because RLM is operating under UDP, it needs to retransmit the control packet if the packet is not acknowledged within this retransmit interval.

switch-link	The maximum transition period allows RLM to switch from a lower preference link to a higher preference link. If the switching link does not complete successfully before this timer expires, RLM will go into the recovery state.

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.

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.

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} command in EXEC mode, use the tn3270 8bit display command in line configuration mode. Use the no form of this command to restore the default 7-bit mask used for TN3270 connections.

tn3270 8bit display

no tn3270 8bit display

Syntax Description

This command has no arguments or keywords.

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} command in EXEC mode, use the tn3270 8bit transparent-mode command in line configuration mode. Use the no form of this command to restore the default 7-bit mask used for TN3270 connections.

tn3270 8bit transparent-mode

no tn3270 8bit transparent-mode

Syntax Description

This command has no arguments or keywords.

tn3270 character-map

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

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

(Optional) Hexadecimal value of an ASCII character.

all

Indicates all character mappings.

tn3270 datastream

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

tn3270 datastream {extended | normal}

no tn3270 datastream

Syntax Description

extended

Extended datastream.

normal

Normal datastream.

tn3270 null-processing

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

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.

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, issue the tn3270 optimize-cursor-move command in global configuration mode. Use the no form of the command to ensure that all cursor movement information is sent between the user's terminal and the TN3270 host.

tn3270 optimize-cursor-move

no tn3270 optimize-cursor-move

Syntax Description

This command has no arguments or keywords.

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. Use the no form of the command to return to the default of no reset required.

tn3270 reset-required

no tn3270 reset-required

Syntax Description

This command has no arguments or keywords.

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. Use the no form of this command to save bandwidth on asynchronous lines by not displaying status messages.

tn3270 status-message

no tn3270 status-message

Syntax Description

This command has no arguments or keywords.

tn3270 typeahead

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

tn3270 typeahead

no tn3270 typeahead

Syntax Description

This command has no arguments or keywords.

ebcdic-in-hex	Hexadecimal value of an EBCDIC character.
ascii-in-hex	(Optional) Hexadecimal value of an ASCII character.
all	Indicates all character mappings.

extended	Extended datastream.
normal	Normal datastream.

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.

Table of Contents

Cisco IOS Dial Services Commands: SL Through TN