<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 security? Context: A firewall in computer security functions as a barrier that filters and controls network traffic between trusted and untrusted networks based on applied rules. Answer: [/INST]A firewall acts as a barrier between a trusted network and an untrusted network, filtering and controlling incoming and outgoing network traffic based on an applied rule set.</s>