> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On
> Behalf Of Pachiappan D
> Sent: Tuesday, July 29, 2008 11:36 AM
> I use net-snmp 5.4.1 and am using "snmpgetnext" to retrieve
> the table rows/columns.
>
> To retrieve a row , i did as below,
> snmpgetnext -v3 -uadmin -lauthNoPriv -aMD5 -Apassword
> localhost ifTable - gives the first row ( 1st column )
> IF-MIB::ifIndex.1 = INTEGER: 1
>
> snmpgetnext -v3 -uadmin -lauthNoPriv -aMD5 -Apassword
> localhost ifTable.1 ( Index1 of 3 ) - Need to give the second
> row (1st column )
> IF-MIB::ifIndex.1 = INTEGER: 1 ( i am getting the first row
> again wrongly )
>
> Can anyone help me on this?
The MIB says:
[SNIP]
ifTable OBJECT-TYPE
SYNTAX SEQUENCE OF IfEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A list of interface entries. The number of entries is
given by the value of ifNumber."
::= { interfaces 2 }
[/SNIP]
...so that's the base of our table. Next:
[SNIP]
ifEntry OBJECT-TYPE
SYNTAX IfEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An entry containing management information applicable to a
particular interface."
INDEX { ifIndex }
::= { ifTable 1 }
[/SNIP]
You'll see this in every table. Don't ask why - it just has to be
there[1]. Note that it attaches to ifTable. After this:
[SNIP]
IfEntry ::=
SEQUENCE {
ifIndex InterfaceIndex,
ifDescr DisplayString,
ifType IANAifType,
ifMtu Integer32,
ifSpeed Gauge32,
ifPhysAddress PhysAddress,
ifAdminStatus INTEGER,
ifOperStatus INTEGER,
ifLastChange TimeTicks,
ifInOctets Counter32,
ifInUcastPkts Counter32,
ifInNUcastPkts Counter32, -- deprecated
ifInDiscards Counter32,
ifInErrors Counter32,
ifInUnknownProtos Counter32,
ifOutOctets Counter32,
ifOutUcastPkts Counter32,
ifOutNUcastPkts Counter32, -- deprecated
ifOutDiscards Counter32,
ifOutErrors Counter32,
ifOutQLen Gauge32, -- deprecated
ifSpecific OBJECT IDENTIFIER -- deprecated
}
[/SNIP]
This is another if those "don't ask" type of features that must be
there[1]. After that:
[SNIP]
ifIndex OBJECT-TYPE
SYNTAX InterfaceIndex
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"A unique value, greater than zero, for each interface. It
is recommended that values are assigned contiguously
starting from 1. The value for each interface sub-layer
must remain constant at least from one re-initialization of
the entity's network management system to the next re-
initialization."
::= { ifEntry 1 }
[/SNIP]
You will never see one of these objects. Why? Because it's an index
(see the INDEX clause of ifEntry), and in SNMP indices are never returned as
objects, since they are already included as part of the OID. After that:
[SNIP]
ifDescr OBJECT-TYPE
SYNTAX DisplayString (SIZE (0..255))
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"A textual string containing information about the
interface. This string should include the name of the
manufacturer, the product name and the version of the
interface hardware/software."
::= { ifEntry 2 }
[/SNIP]
...which is the first returnable object. Note that, like ifIndex, this
is attached to ifEntry, not ifTable.
To sum it all up the first returnable object is
ifTable.ifEntry.ifDescr, or ifTable.1.2 . If you get next on ifTable, the
correct response is ifTable.1.2.(first index). If you get next on ifIndex.1,
or ifTable.1.1, the correct response is ifTable.1.2.(first index).
Note that ifIndex is not guarant3eed to start at 1, nor are values
guaranteed to be contiguous.
You may be interested in the snmptable command.
HTH,
Mike
[1] - Not that you should never ask - it's just not relevant to the immediate
problem.
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