As we created our own global regular expression, you probably noticed that there were a few already existing there.

Let's navigate to Administration | General and choose Regular expressions in the drop-down again. Besides the one we created for the loopback interface filtering, there are five existing expressions:

The expressions shown in the preceding screenshot can be shown as follows:

• One of them, Network interfaces for discovery, actually does almost the same thing as ours did, except that it also excludes interfaces whose names start with Software Loopback Interface, which is for MS Windows monitoring.
• File systems for discovery can be used to limit the types of filesystems to monitor, besides xfs, which we filtered for; it includes a whole bunch of other filesystem types.
• Storage devices for SNMP discovery excludes memory statistics from storage devices when monitoring over SNMP. Windows service names for discovery is used to exclude services that we don't need to know the status of in Windows and could easily get extended.
• The final one, Windows service startup states for discovery, will exclude services not marked as to start automatically or automatic delayed.