URL: enter the URL to fetch
Hostnames: enter hostnames (one per line) to resolve via DNS
Manual: enter IP addresses directly
MySQL: JSON config with {"host": "hostname", "port": 3306, "user": "username", "password": "password", "database": "dbname", "query": "SELECT ip FROM table"}
Computed: JSON config with {"operation": "addition|subtraction|intersection", "sources": ["list1", "list2"]}