Change TELNET Attributes (CHGTELNA)

The Change TELNET Attributes (CHGTELNA) command is used to change configurable TELNET attributes. The changes take effect the next time the TELNET server is started either by the Start TCP/IP (STRTCP) command or by the Start TCP/IP Server (STRTCPSVR) command.

Note: The CHGTELNA command parameters are used by the TELNET server only; they are not used by the TELNET client. Many of these same parameters can be set for TELNET clients using the Start TCP/IP TELNET (STRTCPTELN) command or the TELNET client subcommands.

Restrictions:

You must have input/output system configuration (*IOSYSCFG) special authority to use this command.

Parameters

Keyword	Description	Choices	Notes
AUTOSTART	Autostart server	YES, NO, *SAME	Optional, Positional 1
NBRSVR	Number servers	1-200, SAME, CALC	Optional
TIMMRKTIMO	Session keep alive timeout	0-2147483647, SAME, CALC, *DFT	Optional
DFTNVTTYPE	Default NVT type	SAME, VT100, *NVT	Optional
CCSID	Coded character set identifier	1-65533, SAME, MULTINAT, BRITISH, DUTCH, FINNISH, FRENCH, FRENCHCAN, GERMAN, ITALIAN, NORDAN, SPANISH, SWEDISH, *SWISS	Optional
TBLVTOUT	ASCII fullscreen mapping	Single values: SAME, CCSID, DFT Other values: Element list*	Optional
	Element 1: Outgoing EBCDIC/ASCII table	Qualified object name
	Qualifier 1: Outgoing EBCDIC/ASCII table	Name
	Qualifier 2: Library	Name, LIBL, CURLIB
TBLVTIN		Single values: SAME, CCSID, DFT Other values: Element list*	Optional
	Element 1: Incoming ASCII/EBCDIC table	Qualified object name
	Qualifier 1: Incoming ASCII/EBCDIC table	Name
	Qualifier 2: Library	Name, LIBL, CURLIB
ALWSSL	Allow Secure Socket Layer	YES, NO, ONLY, SAME	Optional

Top

Number servers (NBRSVR)

Specifies the number of servers to start. TELNET has two types of server jobs 1) TELNET Server jobs and 2) Device Manager jobs. This number indicates the number of jobs started for the device manager server. If the TELNET SSL was started successfully, the number also indicates the number of jobs started for the TELNET server job. If TELNET SSL was not started, there will be one TELNET Server job.

*SAME: The number of servers value does not change if it was previously set. Otherwise, *CALC is used.
*CALC: The number of Servers jobs and Device Manager jobs started will be determined by the system. For more information on how the *CALC value is calculated and considerations if you want to change this value, see the TCP/IP Configuration and Reference .
1-200: Specify the number of servers to start. For example, if you specify 6 and TELNET SSL was started successfully, six TELNET Server jobs and six Device Manager jobs will be started. If TELNET SSL was not started successfully, one TELNET Server job will be started.

Session keep alive timeout (TIMMRKTIMO)

Specifies the number of seconds between connection validation. TCP tests each TELNET connection at the specified time interval. If TCP does not get a response, it ends the connection.

This parameter determines how frequently the session connection is verified. A high value can result in a longer time before a lost connection gets detected. A lower value tests the session more frequently, but if set too low then normal network delays may result in connections being considered lost.

An explanation of keep alive can be found in the help information for command CHGTCPA parameter TCPKEEPALV. Note that TCPKEEPALV is defined in minutes, while TIMMRKTIMO is defined in seconds.

*SAME: The session keep alive value does not change if it was previously set. Otherwise, *CALC is used.
*CALC: The session keep alive is based on the frequency of sampling.
*DFT: The default session keep alive value is set to 600 seconds.
0-2147483647: Specify the number of seconds for the session keep alive timeout. A value of 0 means that there is no timeout.

Default NVT type (DFTNVTTYPE)

Specifies the default Network Virtual Terminal (NVT) type to be used when the TELNET server is not able to negotiate one of the supported types.

*SAME: The default NVT type does not change if it was previously set. Otherwise, *VT100 is used.
*VT100: The TELNET server defaults to VT100 mode when the server and client fail to negotiate one of the supported terminal types. The OS/400 server system operates as if the VT100 terminal type were negotiated.
*NVT: The TELNET server defaults to the network virtual terminal (NVT) mode when the server and client fail to negotiate one of the supported terminal types. NVT mode requires an application program written to interact with NVT workstation devices.

Coded character set identifier (CCSID)

Specifies the ASCII coded character set identifier (CCSID) in use on the VTxxx terminal. CCSID is the default used by TELNET for ASCII full-screen mapping. The ASCII CCSID value is used to map between the EBCDIC CCSID of the job and the national replacement character set or the ASCII CCSID value selected with the CCSID parameter. This value is used by VTxxx users when they sign on the OS/400 system.

Outgoing and incoming mapping can optionally be done with mapping tables defined in the TBLVTOUT and TBLVTIN parameters. Normally the TBLVTOUT and TBLVTIN parameters are set to the default of *CCSID or *DFT. Both parameters indicate that the value used in the CCSID parameter is used for mapping. If a mapping table is to be used for outgoing mapping, a table object can be specified in the TBLVTOUT parameter. The table object specified in the TBLVTOUT parameter is used instead of the CCSID value.

Incoming mapping can be changed to use a mapping table by specifying a table object in the TBLVTIN parameter. This mapping table overrides the specified CCSID value and is used for incoming mapping.

The national replacement character set special values allowed for the CCSID parameter are the Digital Equipment Corporation (DEC) standard character sets. A numeric CCSID value can be used optionally to identify the required ASCII-to-EBCDIC and EBCDIC-to-ASCII mapping. If a numeric CCSID value is chosen, it is validated to ensure it is a valid ASCII CCSID value that is available on the current system.

*SAME: The default CCSID value does not change if it was previously set. Otherwise, *MULTINAT is used.
*MULTINAT: The DEC multinational character set is in use.
*BRITISH: The DEC British national replacement character set is in use.
*DUTCH: The DEC Dutch national replacement character set is in use.
*FINNISH: The DEC Finnish national replacement character set is in use.
*FRENCH: The DEC French national replacement character set is in use.
*FRENCHCAN: The DEC French Canadian national replacement character set is in use.
*GERMAN: The DEC German national replacement character set is in use.
*ITALIAN: The DEC Italian national replacement character set is in use.
*NORDAN: The DEC Norwegian/Danish national replacement character set is in use.
*SPANISH: The DEC Spanish national replacement character set is in use.
*SWEDISH: The DEC Swedish national replacement character set is in use.
*SWISS: The DEC Swiss national replacement character set is in use.
1-65533: The requested CCSID value is used. This value is validated to ensure a valid ASCII CCSID was requested.
Note: Only ISO 7-bit and ISO 8-bit ASCII CCSID values can be specified.

Outgoing EBCDIC/ASCII table (TBLVTOUT)

Specifies the outgoing mapping table used by the TELNET server to map outgoing data when in an ASCII full-screen session. All outgoing data is mapped from EBCDIC to ASCII.

If a table object is specified for the TBLVTOUT parameter, the table object is used for outgoing mapping. Otherwise, the CCSID parameter is used for outgoing mapping.

Single values

*SAME: The default TBLVTOUT value does not change if it was previously set. Otherwise, *CCSID is used.
*CCSID: The CCSID parameter is used to determine outgoing mapping.
*DFT: The CCSID parameter is used to determine outgoing mapping.

Qualifier 1: Outgoing EBCDIC/ASCII table

name: Specify the name of the outgoing mapping table. This mapping table is used instead of the default mapping specified by the CCSID parameter.

Qualifier 2: Library

*LIBL: All libraries in the user and system portions of the job's library list are searched until the first match is found.
*CURLIB: The current library for the job is searched. If no library is specified as the current library for the job, the QGPL library is used.
name: Specify the name of the library to be searched.

Incoming ASCII/EBCDIC table (TBLVTIN)

Specifies the incoming mapping table used by the TELNET server to map incoming data when in an ASCII full-screen session. All incoming data is mapped from ASCII to EBCDIC.

If a table object is specified for the TBLVTIN parameter, the table object is used for incoming mapping. Otherwise, the CCSID parameter is used for incoming mapping.

Single values

*SAME: The default TBLVTIN value does not change if it was previously set. Otherwise, *CCSID is used.
*CCSID: The CCSID parameter is used to determine incoming mapping.
*DFT: The CCSID parameter is used to determine incoming mapping.

Qualifier 1: Incoming ASCII/EBCDIC table

name: Specify the name of the incoming mapping table. This mapping table is used instead of the default mapping specified by the CCSID parameter.

Qualifier 2: Library

*LIBL: All libraries in the user and system portions of the job's library list are searched until the first match is found.
*CURLIB: The current library for the job is searched. If no library is specified as the current library for the job, the QGPL library is used.
name: Specify the name of the library to be searched.

Examples

Example 1: Setting the Session Keep Alive Timeout

CHGTELNA   TIMMRKTIMO(600)

This command sets the session keep alive timeout to be 600 seconds. Each TELNET connection will be validated by TCP every 10 minutes. If TCP does not get a response, it ends the connection.

Example 2: Setting the TELNET Autostart Attribute

CHGTELNA   AUTOSTART(*NO)

This command sets the autostart attribute such that the TELNET server will not be started when TCP/IP is started by the STRTCP command or STRTCPSVR SERVER(*AUTOSTART) command.