Hi ariady2004,
Assume that this goes from your network settings between Notification Server and these clients.
If you aren't able to ping by FQDN, Hostname of IP address from cmd line on NS, then network discovery will also unable to discover them. Check dns/firewall settings.
Or if you don't get much information for these clients after completed network discovery, then check credentials and time out value for "WMI", "SNMP" protocols in "Default Connection Profile".
You can create a reg file and install it on Notification Server to get more detailed information during "Network Discovery" task run:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Altiris\DiscoveryTasks\Engine Log]
"IncludePhase5"="1"
"LogWanted"="1"
"LogConnectivity"="1"
"LogLevel"="Verbose"
"LogThreadActivity"="1"
"LogFilePath"="C:\\NetworkDiscoveryTaskLog.txt"
[HKEY_LOCAL_MACHINE\SOFTWARE\Altiris\PluggableProtocols\Debug]
"Level"=dword:00000000
[HKEY_LOCAL_MACHINE\SOFTWARE\Altiris\PluggableProtocols\CimWsMan]
"tracelevel"=dword:0000001f
Thanks,
IP.