1. While troubleshooting a network connection problem for a co-worker, you discover the computer is querying a non-existent DNS server. What command-line utility can you use to assign the correct DNS server IP address? Is DNS using UDP or TCP?
The command-line utility that can be used to assign the correct DNS server IP address is "ipconfig" on Windows or "ifconfig" on Unix/Linux.
DNS primarily uses UDP (User Datagram Protocol) for communication. TCP (Transmission Control Protocol) can be used by DNS in certain situations, such as when the response size exceeds the maximum limit for UDP or in cases where packet loss is detected.
To assign the correct DNS server IP address, you can use the command-line utility called "ipconfig" (Windows) or "ifconfig" (Linux/macOS).
For Windows, follow these steps:
1. Press the Windows key + R to open the Run dialog box.
2. Type "cmd" and press Enter to open the Command Prompt.
3. In the Command Prompt, type "ipconfig /all" and press Enter.
4. Look for the network adapter you need to configure and note the name of the adapter (e.g., Ethernet adapter, Wi-Fi adapter).
5. To set the DNS server IP address, use the command "netsh interface ip set dns [adapter_name] static [dns_server_ip]". Replace [adapter_name] with the name of the adapter and [dns_server_ip] with the correct DNS server IP address. Press Enter to apply the changes.
For Linux/macOS, follow these steps:
1. Open a terminal window.
2. Type "ifconfig" and press Enter to display the network interfaces.
3. Locate the network interface you want to configure, note its name (e.g., eth0, wlan0).
4. To assign the DNS server IP address, use the command "sudo nano /etc/resolv.conf" to edit the resolv.conf file.
5. In the file, add the line "nameserver [dns_server_ip]" with the correct DNS server IP address. Press Ctrl+X to exit nano editor, then press Y and Enter to save the changes.
DNS uses both UDP (User Datagram Protocol) and TCP (Transmission Control Protocol). UDP is used for most DNS queries and responses, while TCP is used in certain scenarios, such as when a DNS response exceeds the maximum size for UDP or when using DNSSEC (DNS Security Extensions).