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DNSQuerySniffer is a lightweight, freeware network sniffer developed by NirSoft that displays all Domain Name System (DNS) queries sent on your system in a clean, spreadsheet-like format. Unlike complex packet analyzers like Wireshark, it isolates DNS traffic natively, making it incredibly simple to detect unauthorized application behavior, network delays, or potential malware activity. 1. How to Set Up and Start Sniffing

To begin capturing data, you need to configure the underlying capture driver and network interface:

Download and Run: Download the utility directly from the official NirSoft DNSQuerySniffer page. It is portable, so you do not need to install it—just extract and run the executable.

Select a Capture Method: Upon opening the tool, a “Capture Options” window will appear. Select a packet capture driver:

Raw Sockets: Works out of the box without extra software, but may miss some packets on certain Windows configurations.

WinPcap / Npcap: Recommended for accuracy. If you already have Wireshark installed, Npcap is likely available on your machine.

Pick the Network Interface: Choose your active network adapter (e.g., Wi-Fi or Ethernet) from the list.

Start Monitoring: Click OK. The tool will immediately start displaying live DNS requests generated by your computer or Active Directory environment. 2. Key Data Fields to Analyze

As traffic flows through, each query is listed as a row with detailed sub-columns. Focus on these critical metrics to understand your traffic:

Host Name (QNAME): The web domain or server address being queried (e.g., google.com).

Query Type: Look for common types like A (IPv4 addresses), AAAA (IPv6 addresses), MX (Mail servers), or TXT (Text records).

Response Code (RCODE): Shows if the request succeeded. No Error (0) means success. NXDOMAIN (3) means the domain does not exist, which often points to typos or malicious malware beaconing.

Duration: The time delta between the query and the response. High duration indicators reveal slow, bottlenecked DNS servers.

IP Addresses / Response String: The literal IP answers returned by the DNS server. 3. Practical Troubleshooting & Security Use Cases 🕵️ Detect Malicious Activity and Data Exfiltration

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