You can Check Inactive computer report
Reports->All reports->Discovery and Inventory->Inventory->Cross-platform->Inventory Agent->Inventory Diagnostics->Under you can find (Computers that have not reported inventory in last N days)
See this thread
http://www.symantec.com/connect/forums/altiris-report-how-works-inactive-machines-report
http://www.symantec.com/connect/forums/altiris-report-type
Also you can check Active computer report
See Igor Perevozchikov Comments
https://www-secure.symantec.com/connect/forums/view-active-computers-altiris-75
Hi,
You can use this SQL query to create your own report in SMP console, to see only active managed computers.
select vc.[Guid] as [ResourceGuid], vc.[Name], ctr.[HasTaskAgent],
ctr.[IsActive],
ctr.[LastRegistered], coalesce( cta.[Product Version], '' ) as [Version],
vc.[IP Address] as [IPAddress],
vc.[Domain],
vc.[OS Name] as [OSName]
from [dbo].[TaskTargetDeviceCache] vc
left outer join [dbo].[Inv_Client_Task_Resources] ctr
on ctr.[_ResourceGuid] = vc.[Guid]
left outer join [dbo].[Inv_Client_Task_Servers] cts
on cts.[ClientTaskServerGuid] = ctr.[ClientTaskServerGuid]
left outer join [dbo].[Inv_AeX_AC_Client_Agent] cta
on cta.[_ResourceGuid] = ctr.[_ResourceGuid]
and lower( cta.[Agent Name] ) = 'altiris client task agent'
where
( vc.[IP Address] is not NULL and LEN(vc.[IP Address])>0 )
AND ctr.[IsActive]='1'
ORDER by Name
ASC