Email alerts on network inventory reports can currently be sent out once per day only, according to your settings under
Configuration\Email alerts. Only alerts about scanned eventlog entries will immediately be sent out. Our next major version will allow you to set up more flexible schedules for report alerts as well, but the full release date of that isn't known yet.
Monitoring of specific assets can be achieved by setting up separate scanning schedules under
Configuration\Scanning methods, section
IP range scanning or
Asset collection scanning. Here you can define scanning intervals of a few hours or minutes. Afterwards create reports on the assets you are interested in which inform you if an asset wasn't scanned during the last X hours (please find an example report below which lists assets having "example" in their asset name and not seen in the last 3 hours).
Select Top 1000000 tblAssets.AssetID,
tblAssets.AssetName,
tsysAssetTypes.AssetTypename,
tsysAssetTypes.AssetTypeIcon10 As icon,
tblAssets.IPAddress,
tblAssets.Lastseen,
tblAssets.Lasttried
From tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Inner Join tsysAssetTypes On tsysAssetTypes.AssetType = tblAssets.Assettype
Where tblAssets.AssetName Like '%example%' And DateDiff(hh, tblAssets.Lastseen,
GetDate()) > 3 And tblAssetCustom.State = 1
You could add this report to a
Data Report widget on your Dashboard in order to have a quick overview or set up email alerts based on it.
More details on how to set up email alerts can be found in
this KB article.