...
- match_dbus
- match_fqdn
- match_dns_fqdn
- match_hostname
- match_dns_hostname
- match_ip
- match_ip_no_data
- match_serial
- match_serial_type
- match_sysname
...
- DBus - if you clone a Linux virtual machine, unless you manually regenerate this (and in my experience, people do not) it will remain the same.
- FQDN - This should be globally unique, but I have seen instances where it is not.
- Hostname - Think of mail.domain1.com and mail.domain2.com - same hostname.
- IP - It is not uncommon to have an overlapping address space in a given Organisation. Not ideal, but not uncommon.
- Serial - It is very common for second tier motherboard manufacturers to not set this, to set it to all 0's or even all F's.
- Sysname - This is settable by users and so even though it should be globally unique, there is certainly no guarantee of this.
...