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).