Question: fire wall is used in communication to save from
[{'answer': 'untrusted external network', 'provenance': [{'wikipedia_id': '26173989', 'title': 'Firewall (computing)', 'start_paragraph_id': 1, 'start_character': 240, 'end_paragraph_id': 1, 'end_character': 266, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '26173989', 'title': 'Firewall (computing)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 288, 'bleu_score': 0.9529077664391161, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2758609815942249979}, 'section': 'Section::::Abstract.'}]}]