clsnmp Command

Purpose

TheAIX® clsnmp command provides the SNMP manager function from the AIX shell to query SNMP agents for network management information.

Syntax

clsnmp [ -d DebugLevel ] [ -h TargetHost ] [ -c Community ] [ -t TimeOutValue ] [ -r RetryNumber ] [ -n NonRepeaters ] [ -m MaxRepetitions ] [ -p PortNumber ] [ -v ] [ -f ConfigurationFile ] [ -? ] Function [ MIBVariable [ VariableType ] [ Value ] [ ... ] ]

Description

Use the clsnmp command to issue SNMP requests to agents and to process SNMP responses returned by agents. The AIX clsnmp commands supports issuance of SNMPv1, SNMPv2c, and SNMPv3 requests.

SNMP request types

findname: Sends a request that a search be done to obtain the textual name, for a given MIBVariable input, whose internal ASN.1 value best matches the input ASN.1 value. The search first checks the /etc/mib.defs file, and if a matching textual name is not found, continue with the compiled MIB. Only one MIBVariable is allowed per clsnmp findname invocation.
get: Sends a request to an SNMP agent for a specific management information base (MIB) variable. clsnmp then waits for a response or times out.
getbulk: Obtains the value of the variables in the MIB tree specified by the OID or MIB variable name. A single getbulk performs the same function as a series of getnexts with fewer data exchanges between the clsnmp command and the SNMP agent.
getnext: Sends a request to an SNMP agent for the next MIB variable that lexicographically follows the MIBVariable specified. clsnmp then waits for a response or times out.
set: Sends a request to an SNMP agent to set a specific MIB variable. clsnmp then waits for a response or times out.
trap: Listens for SNMP traps and displays trap information when they occur. Uses the default, well-known port 162 or the port number specified on the -p option. The clsnmp trap function continues to listen for traps until the process is killed or canceled.
walk: Issues a getnext request for a specified prefix, then continues to issue getnext requests for as long as there are variables that match the specified prefix. A prefix can be any leading portion of the complete object identifier.

Usage

The set operation is not supported on all MIB objects. The set operation may be rejected if the agent or subagents managing the MIB object does not support SET.

getbulk is an SNMPv2 function. If the target agent only supports SNMPv1, the target agent ignores your request. As a result, your request times out.

The function keywords are not case sensitive. The flags, variable names and values are case sensitive.

In order to listen to traps from NetView® SNMP and AIX clsnmp at the same time, use the -p PortNumber parameter on the clsnmp command. Only one management application at an IP address can listen on a port at a time. Specifying -p on the clsnmp trap command enables a port other than well-known port 162 to be used. Both ports must be configured as agent trap destinations.

An clsnmp command that is not authenticated (by using an acceptable community name or user name) will time out.

The clsnmp command uses two configuration files: /etc/mib.defs and clsnmp.conf. Sample files are shipped in the /usr/samples/snmpdv3 directory.

The clsnmp command supports sending SNMPv1, SNMPv2c, and SNMPv3 requests. The file clsnmp uses to determine whether it should send an SNMPv1,SNMPv2c or SNMPv3 request is the clsnmp.conf file. If the target specified by way of the -h parameter matches a winSNMP name in the clsnmp.conf file, clsnmp sends the request using the parameters specified on the entry. If the -h parameter is not specified, then the request will be sent as an SNMPv1request.

Flags

Item	Description
-c Community	Specifies the community name used to access the specified variables at the destination SNMP agent. If you do not specify a community name, the default name is public. Community names are not required when using the user-based security model. Note: Community names are case sensitive.
-d DebugLevel	Specifies the debug level. The default level is 0, which means no debug. The higher the debug level, the greater the number of messages that are displayed. The debug levels are 0-4.
-f ConfigurationFile	Specifies the full path and file name of the configuration file.
-h TargetHost	Specifies the target host to which you want to send a request. The host can be an IPv4 address, an IPv6 address, a host name, or a winSNMP name in the clsnmp.conf configuration file. If you do not specify a host, the default is your local host.
-m MaxRepetitions	Only applies to getbulk. This is ignored if the function request is not a getbulk. Maximum repetitions is the number of lexicographic successors to be returned for each variable binding pair after the first "-n number" successors. For example, starting with successor "-n number"+1, return "-m number" of successors for each variable binding pair. The default is 10.
-n NonRepeaters	Only applies to getbulk requests. This is ignored if the function request is not a getbulk. NonRepeaters is the number of variable binding pairs (name/value), starting with the first, for which only a single successor is returned. The default is 0.
-p PortNumber	Specifies the number of the port that listens for traps. If a port number is not specified, the clsnmp trap function listens on the well-known port 162, the default port for clsnmp traps.
-r RetryNumber	Specifies the maximum number of times to retry the command if it timed out. The default is 2.
-t TimeOutValue	Specifies the amount of time (in seconds) that the clsnmp command waits for a reply from the SNMP agent. The default is 3.
-v	Specifies that the output from a request should be displayed using verbose output, for example, using the textual name instead of the MIB object identifier.
-?	Displays help information.

Parameters

Item	Description
Function	Specifies the SNMP function/operation to perform, which is one of the following: get, getnext, getbulk, set, walk, trap, findname.
MIBVariable	Specifies the Management Information Base (MIB) object, using its object descriptor (textual name), object identifier in ASN.1 notation, or a combination of the two. When used with walk, this is the MIB object prefix. A prefix can be any leading portion of the complete object identifier. When used with findname, this is the object identifier in ASN.1 notation.
Value	Specifies the value to be set by the SET function. If white space is needed in the value, you must enclose the value in double quotes ("). If you want to set a variable to a value that is also a type, you must specify the type.
VariableType	Specifies the type of value being set. To complete an SNMP SET request, the SMI_type must be known. If no type is specified, clsnmp searches first the /etc/mib.defs file and then the compiled MIB to determine the type. If the variable is not found, an error is returned. If a VariableType is specified, the VariableType takes precedence over any type that may be assigned in the MIB. The VariableType and value must be compatible. For example, if you specify a type of "number" and a value of "foo," an error is returned because "foo" is not a number. VariableType is not case sensitive. Valid variable types are: bitstring counter counter32 counter64 display or displaystring gauge gauge32 integer integer32 ipaddress nsapaddress null objectidentifier or OID octetstring opaque opaqueascii timeticks uinteger

Limitation

When the snmpdv3 daemon encounters SMI-v2 data type MIB while processing a SNMPv1 protocol request from the clsnmp manager, it skips the MIB until it finds a SMI-v1 data type MIB.

Work around

The clsnmp manager should be configured with SNMPv2 type requests or SNMPv3 type requests to dump all of the MIB variables with the snmpdv3 daemon.

Examples

Getting the MIB variable.
1. The following requests MIB object sysName.0:
```
clsnmp get sysName.0
```
  The output from this command looks similar to:
```
1.3.6.1.2.1.1.5.0 = hostname.austin.ibm.com
```
2. The following requests MIB object myName.0, where myName is defined in the /etc/mib.defs file to be the same object identified by sysName.0:
```
clsnmp get myName.0
```
  The output from this commands looks similar to:
```
1.3.6.1.2.1.1.5.0 = myhostname.austin.ibm.com
```
3. The following requests MIB object sysName.0 through an IPv6 address:
```
clsnmp -h 2000:1:1:1:209:6bff:feae:6d67 get sysName.0
```
  The output from this command looks similar to:
```
1.3.6.1.2.1.1.5.0 = hostname.austin.ibm.com
```
Getting the next MIB variable.
1. The following requests the next logical MIB object:
```
clsnmp getnext udp
```
  The output from this command looks similar to:
```
1.3.6.1.2.1.7.1.0 = 653
```
2. The following requests the next logical object, using the -v option to have value displayed with textual name instead of object identifier:
```
clsnmp -v getnext udp
```
  The output from this command looks similar to:
```
udpInDatagrams.0 = 653
```
Setting the MIB variable.
1. The following sets MIB object sysName.0 to a value of 'hostname.austin.ibm.com':
```
clsnmp set sysName.0  "hostname.austin.ibm.com"
```
  This command produces output similar to:
```
1.3.6.1.2.1.1.5.0 = hostname.austin.ibm.com
```
2. The value of MIB object sysName.0 can also be set using the VariableType parameter to specify the type of value being set, as in the following example:
```
clsnmp set sysName.0 displayname "hostname.austin.ibm.com"
```
  This command produces output similar to:
```
1.3.6.1.2.1.1.5.0 = hostname.austin.ibm.com
```

Walking the MIB tree.

The following returns by name all objects beginning with the same object identifier prefix, but with fewer data packages to be exchanged between the clsnmp command and the SNMP agent:

clsnmp -h loopback -v -m 10 bulkwalk udp

The output of this command looks similar to the following:

clsnmp -v walk udp 
udpInDatagrams.0 = 653 
udpNoPorts.0 = 22 
udpInErrors.0 = 0 
udpOutDatagrams.0 = 678 
udpLocalAddress.0.0.0.0.7 = 0.0.0.0 
udpLocalAddress.0.0.0.0.9 = 0.0.0.0 
udpLocalAddress.0.0.0.0.13 = 0.0.0.0 
udpLocalAddress.0.0.0.0.19 = 0.0.0.0 
udpLocalAddress.0.0.0.0.37 = 0.0.0.0 
udpLocalAddress.0.0.0.0.161 = 0.0.0.0 
udpLocalAddress.0.0.0.0.5020 = 0.0.0.0 
udpLocalPort.0.0.0.0.7 = 7 
udpLocalPort.0.0.0.0.9 = 9 
udpLocalPort.0.0.0.0.13 = 13 
udpLocalPort.0.0.0.0.19 = 19 
udpLocalPort.0.0.0.0.37 = 37 
udpLocalPort.0.0.0.0.161 = 161 
udpLocalPort.0.0.0.0.5020 = 5020

Getting multiple MIB variables.
The following requests multiple MIB objects using the getbulk request type. The getbulk request type returns the next logical object for one or more MIB objects listed on the command. In the following example, the -n option indicates that only one next logical object is requested for the first two variables (sysLocation and ifTable). For all the other objects in the list (tcp, udp, and icmp), the -m option indicates that 5 repetitions are requested.
Note: The getbulk request type is an SNMPv2 function. The -h parameter identifies a host, loopback, defined in the clsnmp.conf file as an agent that supports SNMPv2 or SNMPv3.
```
clsnmp -h loopback -v -n 2 -m 5 getbulk sysLocation ifTable tcp udp icmp
```
This command produces output similar to the following:
```
sysLocation.0 = Research Triangle Park, NC 
ifIndex.1 = 1 
tcpRtoAlgorithm.0 = 4 
udpInDatagrams.0 = 782 
icmpInMsgs.0 = 22 
tcpRtoMin.0 = 0 
udpNoPorts.0 = 22 
icmpInErrors.0 = 0 
tcpRtoMax.0 = 120 
udpInErrors.0 = 0 
icmpInDestUnreachs.0 = 22 
tcpMaxConn.0 = -1 
udpOutDatagrams.0 = 807 
icmpInTimeExcds.0 = 0 
tcpActiveOpens.0 = 1 
udpLocalAddress.0.0.0.0.7 = 0.0.0.0 
icmpInParmProbs.0 = 0
```
Finding the name of an ASN.1 variable.
The following sends a request that a search be done to obtain the textual name, for a given MIBVariable input, whose internal ASN.1 value best matches the input ASN.1 value. The search begins with the /etc/mib.defs file and, if not found, continues with the compiled MIB. Only one MIBVariable is allowed per clsnmp findname invocation. For example, this can be done with a command similar to the following:
```
clsnmp findname 1.3.6.1.2.1.6.13.1.2
```
This command produces output similar to the following:
```
1.3.6.1.2.1.6.13.1.2 found as: tcpConnLocalAddress
```
A similar example is:
```
clsnmp findname 1.3.6.1.2.1.6.13.1.2.0
```
This command produces output similar to the following:
```
1.3.6.1.2.1.6.13.1.2.0 found as: tcpConnLocalAddress.0
```
Another similar example is:
```
clsnmp findname 1.3.6.1.2.
```
This command produces output similar to the following:
```
1.3.6.1.2. found as: mgmt
```
Issuing an SNMPv3 request.
1. If an winSnmpName entry is configured in /etc/clsnmp.conf file on the manager host with an entry like the following (all on one line):
```
target1   9.3.149.26 snmpv3 u1 -          - AuthNoPriv   HMAC-SHA
76784e5935acd6033a855df1fac42acb187aa867 -   -
```
  and on the snmpd agent machine 9.3.149.26, user u1 is properly configured, then we can issue command on the manager host:
```
clsnmp -v -h target1 get sysName.0
```
  This command will produce output similar to:
```
sysName.0 = somehostname.austin.ibm.com
```
2. It is simple to issue a trap command, as follows:
```
clsnmp trap
```
  Note: If the security model of the trap received is SNMPv3, make sure on the manage station where is listens to the trap has the /etc/clsnmp.conf file properly configured in order to receive the trap.

Files

Item	Description
/etc/clsnmp.conf	Configuration file for the clsnmp command.
/etc/mib.defs	Defines the Management Information Base (MIB) variables the SNMP agent and manager should recognize and handle.