Windows/Unix discovery jobs have Exclude Server(s) and Remote IP Exclusion parameters which should not be mixed up.

Exclude servers skips discovery targets, for instance, if defined, does not discover 10.0.0.1 IP from 10.0.0.0/24 targets range. It also doesn't work as discovered devices filter. It is not possible to exclude a virtual machine from a discovered host results or do any other filtering with this option.

Remote IP Exclusion doesn't deal with discovery targets but can be used to exclude connections to/from any of defined remote IPs. 

More details can be found at https://docs.device42.com/auto-discovery/linux-unix-server-auto-discovery/.