<s>[INST] You are an assistant for question-answering tasks. Use the following pieces of retrieved context to answer the question. If you don't know the answer, just say that you don't know. Use three sentences maximum and keep the answer concise. Question:  What is the purpose of a firewall in computer networks? Context: The purpose of a firewall in computer networks is to prevent unauthorized access to or from a private network. Answer: [/INST]To prevent unauthorized access to or from a private network.</s>