I would like some tips on how to see a list of active users using SNMP and a Linux PC. Can anyone help me? What command do I use and what is the MIB I should examine using this command?

You could get a list of the oid's from The problem you will have is getting the oids since they change dynamically.

The book mentions:

CISCO-AAA-SESSION-MIB

Note that this MIB is supported only when ppp package is installed. It reports both ppp and hotspot active users

enterprises.cisco.ciscoMgmt.ciscoAAASessionMIB.casnMIBObjects.casnActive.casnActiveTableEntries
enterprises.cisco.ciscoMgmt.ciscoAAASessionMIB.casnMIBObjects.casnActive.casnActiveTable.casnActiveEntry.casnSessionId
enterprises.cisco.ciscoMgmt.ciscoAAASessionMIB.casnMIBObjects.casnActive.casnActiveTable.casnActiveEntry.casnUserId
enterprises.cisco.ciscoMgmt.ciscoAAASessionMIB.casnMIBObjects.casnActive.casnActiveTable.casnActiveEntry.casnIpAddr

But I cannot get it working in Linux. Does someone has a simple way of checking this using Linux? Using 'snmpwalk' maybe?

I too wanted to do this.

I am stuck at the following step.

Using Getif and the second last option MBrowser I obtained this entry
' enterprises.9.9.150.1.1.1.0 ' and on selecting this entry (amongst the many such obtained) i got this OID as the associated one
.1.3.6.1.4.1.9.9.150.1.1.1.0

I added this entry using the "Add to Graph" button on this page. Now on the last option Graph page, i am getting a graph listing the number of users connected in 5 sec intervals.

Now if someone can convert this info into some more meaningful graph and also with a history........