[mrtg] 'did not eval into defined data' when querying explicit OIDs

Brian Stiff bstiff at gmail.com
Fri Jul 7 04:31:49 MEST 2006

Thanks Tobias and all for your software and your effort supporting the

I have a running configuration to monitor interface activity on a Cisco IOS
router.  No problems with the initials setup.  I'm adding configuration to
MRTG to monitor IOS Firewall activity, using the new Cisco Unified Firewall
MIB which became available in 12.4(6)T software in February:


I don't get any values for the two OIDs I'm trying to monitor, Active
Sessions and Half-Open Sessions.  Instead, the log indicates the OIDs 'did
not eval into defined data'.  I've used the iReasoning MIB Browser to verify
that the values in the OIDs change, and as mentioned, interface counters are
functioning well in mrtg.

Do I need to load the MIB if I specify the OID?  I can reply with a link to
the MIB itself if you'll need it.

Help will be appreciated, I've been unable to determine what's causing the
'did not eval' message.  Thanks.

Here are the relevant sections of the MRTG config I'm trying to use:



Target[]: at
MaxBytes[]: 1000
Ylegend[]: # Sessions
LegendI[]:Half-open Sessions
LegendO[]:Active Sessions
Title[]: Firewall Activity
PageTop[]: <h1>Firewall Activity</h1>
                <div id="sysdetails">
                                        <td>Active CBAC Sessions</td>
Options[]: gauge


Here is the error output in the log:

2006-07-06 19:30:01 -- Started mrtg with config '/etc/mrtg/mymrtg.cfg'
2006-07-06 19:30:02 -- SNMP Error:
Received SNMP response with error code
  error status: noSuchName
  index 1 (OID: )
SNMPv1_Session (remote host: "" [].161)
                  community: "[deleted]"
                 request ID: 1437776452
                PDU bufsize: 8000 bytes
                    timeout: 2s
                    retries: 5
                    backoff: 1)
 at /usr/bin/../lib/mrtg2/SNMP_util.pm line 490
2006-07-06 19:30:02 -- SNMPGET Problem for
. sysUptime sysName on [deleted]@
 at /usr/bin/mrtg line 1921
2006-07-06 19:30:02 -- ERROR: Target[][_IN_] '
{$mode} ' did not eval into defined data
2006-07-06 19:30:02 -- ERROR: Target[][_OUT_] '
]{$mode} ' did not eval into defined data

Thanks again.


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