Verify SNMP and(or) CIM are configured correctly on all machines.

 

<ADMIN NOTE: Broken link has been removed from this post by Dell>

and

 

There is also a troublshooting tool on the main menu to help configure the protocols.  Remember that desktops (opti, lattitude and precision only) can Only use CIM.  Servers can use both SNMP and CIM.

 

CIM requires a domain admin accout to perform remote WMI queries and it will have problems over some WANs due to the nature of RPCs.

 

IT Assistant only manages Dell instrumented devices so after you have discovered all Dell equipment you can go into the global discovery setting and select 'only dell instrumented devices' then you will not see non-dell equipment in ITA.