In a report, click on Report Options and select Filter by.
Click Add Criteria, which prompts you to enter criteria in fields. By default, first field is Category. Click the down arrow. In drop-down menu, select More Fields. In the drop-down menu, select Log Source.
The filtered field displays: Log Source is blank field. Enter the proxy IP address. To filter by more than one proxy, click the plus (+) sign to add a field.