How To Get Information About Users Connected To The TTY By Using SNMP
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Contents
Introduction
This document describes how you can retrieve information about users connected to the TTY lines on a Cisco device with the help of Simple Network Management Protocol (SNMP). This document also explains all possible object identifiers (OIDs) and how to clear a specific TTY line with SNMP.
Prerequisites
Requirements
Before you use the information in this document, make sure that you meet these requirements:
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Understand how to view TTY information on Cisco devices .
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General use of SNMP walk, get, and set commands.
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Understand how to configure SNMP on a Cisco device.
Components Used
This document applies to Cisco routers and switches running a regular Catalyst operating system (OS) or Catalyst IOS that supports the OLD-CISCO-TS-MIB.
Note: The OLD-CISCO-TS-MIB is not loaded by default in NET-SNMP. If the Management Information Base (MIB) is not loaded on your system, you must use the OID instead of the object name.
The information in this document is based on the software and hardware versions listed here:
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Router c3640 running 12.2(13a)
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NET-SNMP version 5.0.6 available at http://www.net-snmp.org/
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
Conventions
For more information on document conventions, refer to the Cisco Technical Tips Conventions.
Background
Details of the MIB Variables (Includes OIDs)
1.3.6.1.4.1.9.2.9.1 (OLD-CISCO-TS-MIB)
tsLines OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION "Number of terminal lines on this device. Includes virtual lines."
::= { lts 1 }
1.3.6.1.4.1.9.2.9.2.1.1 (OLD-CISCO-TS-MIB)
tsLineActive OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION "Boolean whether this line is active or not."
::= { ltsLineEntry 1 }
1.3.6.1.4.1.9.2.9.2.1.2 (OLD-CISCO-TS-MIB)
tsLineType OBJECT-TYPE
SYNTAX INTEGER {
unknown(1),
console(2),
terminal(3),
line-printer(4),
virtual-terminal(5),
auxiliary(6)
}
ACCESS read-only
STATUS mandatory
DESCRIPTION "Type of line."
::= { ltsLineEntry 2 }
1.3.6.1.4.1.9.2.9.2.1.21 (OLD-CISCO-TS-MIB)
tsLineTimeActive OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION "The time in seconds since line was activated."
::= { ltsLineEntry 21 }
1.3.6.1.4.1.9.2.9.2.1.18 (OLD-CISCO-TS-MIB)
tsLineUser OBJECT-TYPE
SYNTAX DisplayString
ACCESS read-only
STATUS mandatory
DESCRIPTION "TACACS user name,if TACACS is enabled, of user on this line."
::= { ltsLineEntry 18 }
1.3.6.1.4.1.9.2.9.4 (OLD-CISCO-TS-MIB)
tsMsgTtyLine OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS mandatory
DESCRIPTION "tty line to send the message to. -1 sends the messages to all tty lines."
::= { lts 4 }
1.3.6.1.4.1.9.2.9.10 (OLD-CISCO-TS-MIB)
tsClrTtyLine OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS mandatory
DESCRIPTION "tty line to clear. Read returns the last line cleared.
A value of -1 indicates no lines have been cleared."
::= { lts 10 }
Obtain TTY Information with SNMP
Step-by-Step Instructions
The values in the example are as follows:
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Device hostname = ponch
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Read community = public
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Write community = private
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Replace the community strings and the hostname in the these commands.
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To find the available number of TTY lines (that includes the virtual ones), query the object tsLines:
snmpwalk -c public ponch tsLines cisco.local.lts.tsLines.0 : INTEGER: 135
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To list active TTY lines query the tsLineActive object. The active TTY lines return 1:
snmpwalk -c public ponch tsLineActive cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineActive.0 : INTEGER: 1 cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineActive.129 : INTEGER: 0 cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineActive.130 : INTEGER: 1 …
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Verify this with the show users command on the command-line interface (CLI) of the router:
ponch#sh users Line User Host(s) Idle Location 0 con 0 idle 15:32:49 *130 vty 0 idle 00:00:00 10.61.64.9 Interface User Mode Idle Peer Address-
To obtain the type of line, query the tsLineType object. This shows how the user is connected:
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unknown(1)
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console(2)
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terminal(3)
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line-printer(4)
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auxiliary(6)
snmpwalk -c public ponch tsLineType cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineType.0 : INTEGER: console cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineType.129 : INTEGER: auxiliary cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineType.130 : INTEGER: virtual-terminal …
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To determine whether the time line is been active,query the tsLineTimeActive object. This is the time in seconds since the line was activated:
snmpwalk -c public ponch tsLineTimeActive cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineTimeActive.0 : INTEGER: 172351 cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineTimeActive.129 : INTEGER: 0 cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineTimeActive.130 : INTEGER: 9069 …
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To see who is connected to a TTY, you must be connected to the device through TACACS. Query the tsLineUser object to find the user name:
Note: If you are NOT connected through TACACS, then tsLineUser is empty!
snmpwalk -c public ponch tsLineUser cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineUser.0 : DISPLAY STRING- (ascii): cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineUser.129 : DISPLAY STRING- (ascii): cisco.local.lts.ltsLineTable.ltsLineEntry.tsLineUser.131 : DISPLAY STRING- (ascii): cisco …
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Compare this sample output to your CLI command show users output:
ponch#sh users Line User Host(s) Idle Location 0 con 0 idle 15:32:49 *131 vty 0 cisco idle 00:00:00 10.61.64.11 Interface User Mode Idle Peer Address
Clear a VTY Session with SNMP
Step-by-Step Instructions
You can clear a telnet (VTY) session with SNMP. The SNMP command is the equivalent of the clear line vty <number> command. The object used to clear a line is tsClrTtyLine.
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Use SNMP to clear VTY line 132 with these commands:
snmpset -c private ponch tsClrTtyLine.0 integer 132 cisco.local.lts.tcClrTtyLine.0 : INTEGER: 132
or
snmpset -c private ponch .1.3.6.1.4.1.9.2.9.10.0 integer 132 enterprises.9.2.9.10.0 = 132
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To check this on the router before the line 132 is cleared, issue this command on the CLI:
ponch#show users Line User Host(s) Idle Location 0 con 0 idle 05:23:17 130 vty 0 idle 1d03h 144.254.7.118 131 vty 1 idle 1d01h 144.254.7.118 132 vty 2 idle 00:04:36 144.254.8.54 *133 vty 3 idle 00:00:00 144.254.7.53 Interface User Mode Idle Peer Address -
Check the router after you issue this command, to make sure line 132 is cleared:
ponch#show users Line User Host(s) Idle Location 0 con 0 idle 05:26:42 130 vty 0 idle 1d03h 144.254.7.118 131 vty 1 idle 1d01h 144.254.7.118 *133 vty 3 idle 00:00:00 144.254.7.53 Interface User Mode Idle Peer Address -
Line 132 is now cleared.
Note: Issue this command carefully because it can disconnect a user from the device without warning!
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