snmpwalk - retrieve a subtree of management values using SNMP GETNEXT requests
snmpwalk [APPLICATION OPTIONS] [COMMON OPTIONS] AGENT [OID]
snmpwalk is an SNMP application that uses SNMP GETNEXT requests to query
a network entity for a tree of information.
An object identifier (OID) may be given on the command line. This
OID specifies which portion of the object identifier space will be searched
using GETNEXT requests. All variables in the subtree below the given OID are
queried and their values presented to the user. Each variable name is given
in the format specified in variables(5).
If no OID argument is present, snmpwalk will search the
subtree rooted at SNMPv2-SMI::mib-2 (including any MIB object values from
other MIB modules, that are defined as lying within this subtree). If the
network entity has an error processing the request packet, an error packet
will be returned and a message will be shown, helping to pinpoint why the
request was malformed.
If the tree search causes attempts to search beyond the end of the
MIB, the message "End of MIB" will be displayed.
- -Cc
- Do not check whether the returned OIDs are increasing. Some agents
(LaserJets are an example) return OIDs out of order, but can complete the
walk anyway. Other agents return OIDs that are out of order and can cause
snmpwalk to loop indefinitely. By default, snmpwalk tries to
detect this behavior and warns you when it hits an agent acting illegally.
Use -Cc to turn off this check.
- -CE {OID}
- End the walk at the specified OID, rather than a simple subtree. This can
be used to walk a partial subtree, selected columns of a table, or even
two or more tables within a single command.
- -Ci
- Include the given OID in the search range. Normally snmpwalk uses
GETNEXT requests starting with the OID you specified and returns all
results in the MIB subtree rooted at that OID. Sometimes, you may wish to
include the OID specified on the command line in the printed results if it
is a valid OID in the tree itself. This option lets you do this
explicitly.
- -CI
- In fact, the given OID will be retrieved automatically if the main subtree
walk returns no useable values. This allows a walk of a single instance to
behave as generally expected, and return the specified instance value.
This option turns off this final GET request, so a walk of a single
instance will return nothing.
- -Cp
- Upon completion of the walk, print the number of variables found.
- -Ct
- Upon completion of the walk, print the total wall-clock time it took to
collect the data (in seconds). Note that the timer is started just before
the beginning of the data request series and stopped just after it
finishes. Most importantly, this means that it does not include snmp
library initialization, shutdown, argument processing, and any other
overhead.
In addition to these options, snmpwalk takes the common
options described in the snmpcmd(1) manual page.
Note that snmpwalk REQUIRES an argument specifying the agent to query and
at most one OID argument, as described there. The command:
snmpwalk -Os -c public -v 1 zeus system
will retrieve all of the variables under system:
sysDescr.0 = STRING: "SunOS zeus.net.cmu.edu 4.1.3_U1 1
sun4m"
sysObjectID.0 = OID: enterprises.hp.nm.hpsystem.10.1.1
sysUpTime.0 = Timeticks: (155274552) 17 days, 23:19:05
sysContact.0 = STRING: ""
sysName.0 = STRING: "zeus.net.cmu.edu"
sysLocation.0 = STRING: ""
sysServices.0 = INTEGER: 72
(plus the contents of the sysORTable).
The command:
snmpwalk -Os -c public -v 1 -CE sysORTable zeus system
will retrieve the scalar values, but omit the sysORTable.
snmpcmd(1), snmpbulkwalk(1), variables(5).