A very simple example of creating an ACL for a principal and a host:
Creating the ACLS (qith the associated principal) itself.
exec dbms_network_acl_admin.create_acl( acl=>'print_permissions.xml', description=>'Gebruikt voor Print functionaliteit', principal=>'APEX_230100', is_grant=>TRUE, privilege=>'connect');
Associating a host to the ACL:
exec dbms_network_acl_admin.assign_acl( acl=>'print_permissions.xml', host=>'machine-name.domain.domain', lower_port=>8010, upper_port=>8010);
This is a starting point. You can go from here …
(for security reasons I altered some fields)