How to manually configure DNS resolution? Detailed steps and FAQs

　　DNS (Domain Name System) resolution is a core technology of the internet, translating domain names into IP addresses, ensuring network devices can find the correct server. Whether accessing websites, using email services, or connecting to various online resources, DNS resolution works silently behind the scenes. If you would like to manually configure DNS resolution for faster resolution, enhanced security, or to troubleshoot network issues, this article provides detailed steps, common issues, and solutions.

　　Steps for Manually Configuring DNS Resolution:

　　Step 1：Selecting a DNS Server：

　　The first step in manually configuring DNS resolution is selecting the appropriate DNS server. Generally, you can use the default DNS server provided by your ISP, or opt for a third-party DNS service for improved resolution speed and security. Benefits include faster resolution, enhanced security such as DDoS protection and malicious website blocking, and enhanced privacy.

　　Step 2：Configure the operating system's DNS settings：

　　The second step in configuring DNS resolution is to modify the operating system's DNS settings. This can usually be done in two ways:

　　1. Configuring DNS in Windows

• Open the Control Panel and click "Network and Sharing Center."
• In the left-hand menu, click "Change adapter settings."
• Right-click the network connection you're using (such as "Ethernet" or "Wi-Fi") and select "Properties."
• In the window that pops up, select "Internet Protocol Version 4 (TCP/IPv4)" and click "Properties."
• Select "Use the following DNS server addresses" and enter the DNS server addresses of your choice. For example: Preferred DNS server: 8.8.8.8, Alternate DNS server: 8.8.4.4.
• Click "OK" to save your settings.

　　2. Configuring DNS in Linux：

　　In Linux, DNS settings are typically stored in the /etc/resolv.conf file. To manually configure DNS resolution:

　　Open a terminal and edit the /etc/resolv.conf file using a text editor such as nano:

sudo nano /etc/resolv.conf

　　Add or modify the DNS server addresses in the file, save, and exit the editor. The DNS server addresses have been changed.

　　Note: Some Linux distributions use systemd-resolved to manage DNS settings; you may need to edit /etc/systemd/resolved.conf or use the systemctl command to make the changes.

　　3. Configuring DNS in macOS：

• Open "System Preferences" and select "Network."
• Select your current network connection (such as Wi-Fi or Ethernet) on the left and click "Advanced."
• Go to the "DNS" tab and click the "+" button in the lower-left corner to add a new DNS server address.
• Enter the DNS server address and click "OK" to save.

　　Step 3：Configuring DNS resolution caching:

　　Configuring DNS resolution caching is another way to speed up domain name resolution. By caching DNS query results, you can reduce repeated queries and increase web page loading speed.

　　1. Clearing the DNS cache in Windows

　　The Windows operating system caches DNS resolution results to improve subsequent resolution efficiency. If the DNS cache is outdated or has issues, it may cause resolution errors or access failures. To clear the DNS cache, use the following command:

ipconfig /flushdns

　　2. Clearing the DNS Cache in Linux

　　In Linux, the DNS cache is managed by the systemd-resolved service. If you're using a systemd-based distribution, you can clear the DNS cache with the following command:

sudo systemd-resolve --flush-caches

　　For other DNS caching services, such as dnsmasq, you can use the following command:

sudo service dnsmasq restart

　　Configuring a DNS Server:

　　If you need to manage DNS resolution for your own website or server, you can configure a DNS server to handle these requests. There are generally two types of DNS servers: recursive DNS servers and authoritative DNS servers.

　　1. Installing and Configuring a BIND DNS Server (for Linux)

　　BIND is the most common DNS server software. With BIND, you can run an authoritative DNS server and provide domain name resolution services.

　　Installing BIND:

sudo apt-get install bind9

　　Configure BIND:

　　Edit the /etc/bind/named.conf.local file and add the domain name configuration you want to resolve:

zone "example.com" {
    type master;
    file "/etc/bind/db.example.com";
};

　　Then, edit the /etc/bind/db.example.com file and set the DNS record:

$TTL    604800
@       IN      SOA     ns1.example.com. admin.example.com. (
                     2022010101  ; Serial
                     604800      ; Refresh
                     86400       ; Retry
                     2419200     ; Expire
                     604800 )    ; Minimum TTL

        IN      NS      ns1.example.com.
        IN      A       192.0.2.1

　　Start the BIND service:

sudo systemctl start bind9
sudo systemctl enable bind9

　　2. Configure DNS Load Balancing

　　If your server is experiencing heavy traffic, you can configure DNS load balancing to distribute requests across multiple servers. You can configure multiple A records in BIND, pointing to different IP addresses:

www  IN  A  192.0.2.1
www  IN  A  192.0.2.2

　　This way, when a client requests www.example.com, the DNS server will return different IP addresses in a round-robin fashion, achieving load balancing.

　　Frequently Asked Questions and Answers:

　　Q1: Why isn't my DNS resolution working?

　　A: If your DNS resolution isn't working, there are several possible reasons:

　　DNS cache not updated: Try clearing the DNS cache and restarting your browser.

　　DNS server settings incorrect: Ensure you entered the DNS server address correctly and check your network connection.

　　TTL setting too long: DNS records have a TTL (time to live) setting. Before the TTL expires, the DNS server will return cached results. You can force an update by manually clearing the DNS cache.

　　Q2: How do I choose a suitable DNS server?

　　A: When choosing a DNS server, you can consider the following criteria:

　　Resolution speed: Use tools like namebench to test the response speed of different DNS servers.

　　Security: Choose a DNS service with security features such as DDoS protection and DNSSEC support.

　　Privacy: Some DNS service providers offer stronger privacy protections to prevent the collection of user browsing data.

　　Q3: How can I ensure DNS resolution stability?

　　A: To ensure DNS resolution stability, you can configure multiple DNS server addresses to use as backup servers in case the primary DNS server becomes unavailable. Regularly check DNS records to ensure the accuracy of domain name resolution information. Use a reliable DNS service provider to avoid single points of failure.

　　Manually configuring DNS resolution is an effective way to optimize network performance, increase website access speed, and enhance security. By selecting an appropriate DNS server, configuring your operating system's DNS settings, and managing the DNS resolution cache, you can ensure a stable and efficient network environment.