Fix: Can’t Reach DNS Server – Simple Steps

By /

Okay, here’s a comprehensive article (approximately 5000 words) detailing how to fix the “Can’t Reach DNS Server” error, along with explanations and troubleshooting steps:

Fix: Can’t Reach DNS Server – Simple Steps (and Advanced Ones Too!)

The dreaded “Can’t Reach DNS Server” error. It’s a common internet connectivity problem that can strike at any time, leaving you stranded and unable to browse the web. This error message, often accompanied by variations like “DNS Server Not Responding,” “DNS Probe Finished No Internet,” or browser-specific error pages, indicates a breakdown in the crucial process of translating human-readable website names (like google.com) into the numerical IP addresses that computers use to communicate.

This article is your comprehensive guide to understanding, diagnosing, and fixing this issue. We’ll start with the simplest solutions and gradually move towards more advanced troubleshooting techniques. We’ll cover various operating systems (Windows, macOS, Linux) and network setups (home routers, mobile hotspots). Don’t worry if you’re not a tech expert; we’ll explain everything in plain language.

Part 1: Understanding DNS and the Error

Before we dive into fixes, let’s clarify what DNS is and why this error occurs.

1.1 What is DNS?

DNS stands for Domain Name System. Think of it as the internet’s phone book. When you type a website address into your browser, your computer doesn’t directly know where to find that website. It needs the website’s numerical IP address (e.g., 172.217.160.142 for google.com). This is where DNS comes in.

Here’s the process, simplified:

  1. You enter a website address: You type “example.com” into your browser.
  2. Your computer queries your DNS server: Your computer contacts a pre-configured DNS server (usually provided by your Internet Service Provider, or ISP). This server is like a directory assistance operator.
  3. The DNS server looks up the IP address: The DNS server searches its database for the IP address associated with “example.com.”
  4. The DNS server returns the IP address: If the server finds the IP address, it sends it back to your computer.
  5. Your computer connects to the website: Your computer uses the IP address to connect to the website’s server, and the website loads.

1.2 Why Does the “Can’t Reach DNS Server” Error Occur?

The “Can’t Reach DNS Server” error means that step 2 in the process above failed. Your computer tried to contact its designated DNS server but couldn’t get a response. This can happen for various reasons, broadly categorized as:

  • Problems with your local computer:

    • Incorrect DNS server settings.
    • Corrupted DNS cache.
    • Firewall or antivirus software blocking DNS requests.
    • Network adapter issues.
    • Outdated or corrupted network drivers.
    • Problems with your operating system’s network configuration.

  • Problems with your router:

    • Router malfunction or temporary glitch.
    • Incorrect router configuration.
    • Firmware issues.

  • Problems with your ISP:

    • DNS server outage on their end.
    • General internet connectivity issues with your ISP.

  • Problems with the website’s DNS server:

    • The website’s DNS server is down or experiencing problems (less common, but possible).

  • Problems with third-party DNS servers (if you’re using them):

    • The public DNS server you’ve chosen (like Google Public DNS or Cloudflare DNS) is experiencing issues.

Part 2: Simple Fixes (Try These First!)

These are the quickest and easiest solutions to try. They often resolve the issue without requiring any deep technical knowledge.

2.1 Restart Your Computer and Router

This is the classic “turn it off and on again” solution, and it works surprisingly often. Restarting clears temporary glitches and resets network connections.

  • Computer: Shut down your computer completely (not just sleep or hibernate) and then turn it back on.
  • Router: Unplug your router from the power outlet, wait for 30 seconds, and then plug it back in. Wait for all the lights to stabilize (usually takes a few minutes).

2.2 Try a Different Browser

Sometimes, the issue might be specific to a particular browser. Try accessing the internet using a different browser (e.g., if you’re using Chrome, try Firefox, Edge, or Safari). If the problem disappears in another browser, the issue is likely with your original browser’s settings or extensions.

2.3 Check Your Internet Connection

Make sure you have a working internet connection in the first place. Try these steps:

  • Check other devices: See if other devices connected to the same network (phones, tablets, other computers) can access the internet. If they can, the problem is likely with your specific computer. If they can’t, the problem is likely with your router or ISP.
  • Check the router’s lights: Most routers have indicator lights that show the status of the internet connection. Consult your router’s manual to understand what the lights mean. A blinking or red light often indicates a problem.
  • Connect directly to the modem (if possible): If you have a separate modem and router, try connecting your computer directly to the modem with an Ethernet cable. If you can access the internet this way, the problem is with your router.

2.4 Disable Your Firewall and Antivirus (Temporarily!)

Your firewall or antivirus software might be mistakenly blocking DNS requests. Temporarily disable them to see if this resolves the issue.

  • Windows:

    • Search for “Windows Security” and open it.
    • Click on “Firewall & network protection.”
    • Click on your active network profile (usually “Private network”).
    • Turn off the “Microsoft Defender Firewall.”
    • For antivirus, locate your antivirus software’s icon in the system tray (bottom-right corner), right-click it, and look for an option to disable protection temporarily.

  • macOS:

    • Go to System Preferences > Security & Privacy > Firewall.
    • Click the lock icon to make changes (you’ll need your administrator password).
    • Click “Turn Off Firewall.”
    • For antivirus, consult your antivirus software’s documentation for instructions on how to temporarily disable it.

  • Linux:

    • The method for disabling the firewall varies depending on the distribution and firewall software used. Common commands include:
    • sudo ufw disable (for UFW)
    • sudo systemctl stop firewalld (for firewalld)
    • sudo iptables -F (for iptables – Caution: This flushes all rules, use with care!)
    • Consult your distribution’s documentation and your antivirus software’s documentation for specific instructions.

Important: If disabling your firewall or antivirus fixes the problem, re-enable them immediately and then configure them to allow DNS traffic. Leaving your security software disabled is a major security risk. You’ll need to create an exception or rule in your firewall/antivirus settings to allow outbound traffic on UDP port 53 (the standard DNS port).

2.5 Flush Your DNS Cache

Your computer stores a local cache of DNS lookups to speed up future connections. Sometimes, this cache can become corrupted, leading to DNS errors. Flushing the cache forces your computer to get fresh DNS information.

  • Windows:

    1. Open Command Prompt as an administrator:
      • Press the Windows key, type cmd, right-click on “Command Prompt,” and select “Run as administrator.”
    2. Type the following command and press Enter:
      ipconfig /flushdns
    3. You should see a message confirming that the DNS Resolver Cache was successfully flushed.

  • macOS:

    1. Open Terminal (Applications > Utilities > Terminal).
    2. Type the following command and press Enter (you may need to enter your administrator password):
      sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
      (Note: The specific command might vary slightly depending on your macOS version. The above command works for most recent versions.)

  • Linux:

    • The method for flushing the DNS cache depends on the DNS resolver being used. Here are some common scenarios:
      • systemd-resolved (most modern distributions):
        sudo systemd-resolve --flush-caches
      • nscd:
        sudo /etc/init.d/nscd restart
      • dnsmasq:
        sudo /etc/init.d/dnsmasq restart
      • If you’re not sure which resolver you’re using, try each of these commands. One of them should work.

2.6 Check for Malware

Malware can sometimes interfere with your network settings, including DNS. Run a full scan with your antivirus software to check for and remove any malware. Consider using a dedicated anti-malware tool like Malwarebytes for a more thorough scan.

Part 3: Intermediate Fixes (Getting a Bit More Technical)

If the simple fixes haven’t worked, it’s time to delve a little deeper.

3.1 Change Your DNS Servers

Instead of using your ISP’s default DNS servers, you can switch to public DNS servers provided by companies like Google, Cloudflare, or OpenDNS. These servers are often faster and more reliable.

  • Google Public DNS:

    • Preferred DNS server: 8.8.8.8
    • Alternate DNS server: 8.8.4.4

  • Cloudflare DNS:

    • Preferred DNS server: 1.1.1.1
    • Alternate DNS server: 1.0.0.1

  • OpenDNS:

    • Preferred DNS server: 208.67.222.222
    • Alternate DNS server: 208.67.220.220

Here’s how to change your DNS servers on different operating systems:

  • Windows:

    1. Open Network Connections:
      • Press Windows key + R, type ncpa.cpl, and press Enter.
    2. Right-click on your active network connection (Wi-Fi or Ethernet) and select “Properties.”
    3. Select “Internet Protocol Version 4 (TCP/IPv4)” and click “Properties.”
    4. Select “Use the following DNS server addresses.”
    5. Enter the preferred and alternate DNS server addresses (e.g., for Google Public DNS, enter 8.8.8.8 and 8.8.4.4).
    6. Click “OK” and close all windows.
    7. Repeat steps 3-6 for “Internet Protocol Version 6 (TCP/IPv6)” if you’re using IPv6. Use these IPv6 addresses for Google Public DNS:
      • Preferred: 2001:4860:4860::8888
      • Alternate: 2001:4860:4860::8844

  • macOS:

    1. Go to System Preferences > Network.
    2. Select your active network connection (Wi-Fi or Ethernet).
    3. Click “Advanced.”
    4. Go to the “DNS” tab.
    5. Click the “+” button under “DNS Servers.”
    6. Enter the preferred and alternate DNS server addresses.
    7. Click “OK” and then “Apply.”

  • Linux:

    • The method for changing DNS servers varies depending on the distribution and network management tools used. Here are some common scenarios:
      • NetworkManager (most modern distributions):
        1. Click on the network icon in the system tray.
        2. Select “Edit Connections” or “Network Settings.”
        3. Select your active network connection and click “Edit.”
        4. Go to the “IPv4 Settings” tab (and “IPv6 Settings” if applicable).
        5. Change the “Method” to “Automatic (DHCP) addresses only” or “Manual.”
        6. In the “DNS servers” field, enter the preferred and alternate DNS server addresses, separated by commas.
        7. Click “Save.”
      • /etc/resolv.conf (traditional method – may be overwritten by NetworkManager):
        1. Open a terminal.
        2. Edit the /etc/resolv.conf file with a text editor (you’ll need root privileges):
          sudo nano /etc/resolv.conf
        3. Add or modify the nameserver lines:
          nameserver 8.8.8.8
          nameserver 8.8.4.4
          (Replace with your desired DNS server addresses).
        4. Save the file and exit the editor.
        5. Important: Changes to /etc/resolv.conf may be overwritten by network management tools like NetworkManager. If this happens, you’ll need to configure your DNS servers through the network management tool instead.
      • systemd-resolved:
      • Edit /etc/systemd/resolved.conf
        sudo nano /etc/systemd/resolved.conf
      • Under the [Resolve] section, add or uncomment the DNS= line and enter your preferred and alternate servers.
        DNS=8.8.8.8 8.8.4.4
      • Restart the service
        sudo systemctl restart systemd-resolved

3.2 Update Your Network Adapter Drivers

Outdated or corrupted network adapter drivers can cause connectivity problems, including DNS issues.

  • Windows:

    1. Open Device Manager:
      • Press Windows key + X and select “Device Manager.”
    2. Expand “Network adapters.”
    3. Right-click on your network adapter (Wi-Fi or Ethernet) and select “Update driver.”
    4. Choose “Search automatically for drivers.” Windows will try to find and install the latest drivers.
    5. If that doesn’t work, you can visit the website of your computer manufacturer (e.g., Dell, HP, Lenovo) or your network adapter manufacturer (e.g., Intel, Realtek, Broadcom) to download the latest drivers manually.

  • macOS:

    • macOS typically handles driver updates automatically through software updates. Make sure your system is up to date by going to System Preferences > Software Update.

  • Linux:

    • Driver updates are usually handled through your distribution’s package manager. The specific command varies depending on the distribution:
      • Debian/Ubuntu:
        sudo apt update
        sudo apt upgrade
      • Fedora/CentOS/RHEL:
        sudo dnf update
      • Arch Linux:
        sudo pacman -Syu
    • If you have a specific network adapter that requires proprietary drivers, you may need to install them manually. Consult your distribution’s documentation and the network adapter manufacturer’s website for instructions.

3.3 Disable IPv6 (Temporarily)

While IPv6 is the future of internet addressing, some older routers or network configurations might have issues with it. Temporarily disabling IPv6 can sometimes resolve DNS problems.

  • Windows:

    1. Open Network Connections (Windows key + R, ncpa.cpl, Enter).
    2. Right-click on your active network connection and select “Properties.”
    3. Uncheck “Internet Protocol Version 6 (TCP/IPv6).”
    4. Click “OK.”

  • macOS:

    1. Go to System Preferences > Network.
    2. Select your active network connection.
    3. Click “Advanced.”
    4. Go to the “TCP/IP” tab.
    5. Change “Configure IPv6” to “Off” or “Link-local only.”
    6. Click “OK” and then “Apply.”

  • Linux:

    • There are several ways to disable IPv6 on Linux. The most reliable method is to disable it at the kernel level:
      1. Open a terminal.
      2. Edit the /etc/sysctl.conf file:
        sudo nano /etc/sysctl.conf
      3. Add the following lines at the end of the file:
        net.ipv6.conf.all.disable_ipv6 = 1
        net.ipv6.conf.default.disable_ipv6 = 1
        net.ipv6.conf.lo.disable_ipv6 = 1
      4. Save the file and exit the editor.
      5. Apply the changes:
        sudo sysctl -p
      6. To re-enable IPv6, remove these lines from /etc/sysctl.conf and run sudo sysctl -p again.

Important: Disabling IPv6 is generally not recommended as a long-term solution. If it fixes your problem, investigate your router’s IPv6 settings or contact your ISP for assistance in properly configuring IPv6.

3.4 Release and Renew Your IP Address

Your computer gets its IP address from your router (or directly from your ISP if you don’t have a router) using a protocol called DHCP. Sometimes, there can be issues with the IP address assignment, leading to connectivity problems. Releasing and renewing your IP address forces your computer to get a new IP address.

  • Windows:

    1. Open Command Prompt as an administrator.
    2. Type the following commands, pressing Enter after each one:
      ipconfig /release
      ipconfig /renew

  • macOS:

    1. Go to System Preferences > Network.
    2. Select your active network connection.
    3. Click “Advanced.”
    4. Go to the “TCP/IP” tab.
    5. Click “Renew DHCP Lease.”

  • Linux:

    • The command to release and renew your IP address depends on your network configuration. Here are some common scenarios:
    • DHCP Client (dhclient – most common):
      sudo dhclient -r # Release the IP address
      sudo dhclient # Renew the IP address
    • NetworkManager:
      nmcli connection down <connection_name> # Replace <connection_name> with your connection's name (e.g., "Wi-Fi")
      nmcli connection up <connection_name>

3.5 Reset Your Network Settings (Windows)
Windows 10 and 11 include a feature that completely resets all network settings to their defaults. This can be useful if there are deep-seated configuration issues. Warning: This will remove all your saved Wi-Fi networks and passwords, VPN connections, and other network configurations.

  1. Open Settings (Windows key + I).
  2. Go to “Network & Internet.”
  3. Click on “Status” in the left sidebar.
  4. Scroll down and click on “Network reset.”
  5. Click “Reset now.”
  6. Your computer will restart.

3.6 Check Router DNS Settings

Your router also has its own DNS server settings. If these settings are incorrect, it can affect all devices connected to your network.

  1. Access your router’s configuration page:

    • Open a web browser and enter your router’s IP address. The most common addresses are 192.168.1.1, 192.168.0.1, or 192.168.1.254. If you don’t know your router’s IP address, you can find it by:
      • Windows: Open Command Prompt and type ipconfig. Look for “Default Gateway.”
      • macOS: Go to System Preferences > Network > Advanced > TCP/IP. Look for “Router.”
      • Linux: Open a terminal and type ip route | grep default.
    • You will likely be prompted for a username and password. The default credentials are often printed on a sticker on the router itself (usually “admin” for both username and password, or “admin” for the username and a blank password). If you’ve changed the password and forgotten it, you may need to reset your router to its factory defaults (see your router’s manual for instructions).

  2. Locate the DNS settings:

    • The location of the DNS settings varies depending on the router model and manufacturer. Look for sections labeled “Internet,” “WAN,” “Network,” or “DNS.”

  3. Change the DNS server addresses:

    • You can either set your router to use your ISP’s DNS servers automatically (usually the default setting) or enter the addresses of public DNS servers (like Google Public DNS or Cloudflare DNS).

  4. Save the changes and reboot your router.

3.7 Update Router Firmware

Outdated router firmware can contain bugs that cause connectivity problems. Check your router manufacturer’s website for firmware updates and follow their instructions to install them. Caution: Incorrectly updating your router’s firmware can potentially “brick” your router (make it unusable). Make sure you download the correct firmware for your specific router model and follow the instructions carefully.

Part 4: Advanced Troubleshooting

If you’ve tried all the steps above and are still experiencing the “Can’t Reach DNS Server” error, here are some more advanced troubleshooting techniques.

4.1 Check for DNS Leaks

If you’re using a VPN, a DNS leak can cause your DNS requests to be sent through your ISP’s servers instead of your VPN’s servers, potentially leading to connectivity issues. Use a website like https://www.dnsleaktest.com/ to check for DNS leaks.

4.2 Use Network Diagnostic Tools

Operating systems often include built-in network diagnostic tools that can help identify the source of the problem.

  • Windows:

    • Network Troubleshooter: Right-click on the network icon in the system tray and select “Troubleshoot problems.”
    • Ping: Open Command Prompt and type ping google.com. This tests your connection to Google’s servers. If you get replies, your basic internet connection is working. If you get “Request timed out,” there’s a connection problem.
    • Tracert: Open Command Prompt and type tracert google.com. This shows the path your data takes to reach Google’s servers. It can help identify where the connection is failing.

  • macOS:

    • Network Utility: Located in Applications/Utilities. Provides Ping, Traceroute, and other tools.
    • Wireless Diagnostics: Hold down the Option key and click the Wi-Fi icon in the menu bar, then choose “Open Wireless Diagnostics.”

  • Linux:

    • ping: ping google.com (similar to Windows)
    • traceroute: traceroute google.com (similar to Windows tracert)
    • mtr: mtr google.com (combines ping and traceroute)
    • dig: dig google.com (provides detailed DNS lookup information)
    • nslookup: nslookup google.com (another DNS lookup tool)
    • ip: ip addr show (shows network interface information), ip route show (shows routing table)

4.3 Check for Hardware Issues

In rare cases, the problem might be caused by faulty hardware, such as a failing network adapter or a damaged Ethernet cable.

  • Try a different Ethernet cable: If you’re using a wired connection, try a different Ethernet cable to rule out a cable problem.
  • Test your network adapter: If possible, try using a different network adapter (e.g., a USB Wi-Fi adapter) to see if that resolves the issue. If it does, the problem is likely with your original network adapter.

4.4 Contact Your ISP

If you’ve exhausted all other troubleshooting steps, it’s time to contact your ISP. They may be experiencing a DNS server outage or other network problems. They can also help you troubleshoot your specific network configuration.

4.5 Contact the Website Administrator (If Specific to One Site)

If you can access most websites but have trouble with a specific one, the problem might be with that website’s DNS server. Try contacting the website administrator to report the issue.

Part 5: Preventing Future DNS Issues

Once you’ve resolved the “Can’t Reach DNS Server” error, take steps to prevent it from happening again:

  • Keep your software up to date: Regularly update your operating system, browser, network drivers, and router firmware.
  • Use a reliable DNS server: Consider using a public DNS server like Google Public DNS or Cloudflare DNS.
  • Scan for malware regularly: Use a reputable antivirus and anti-malware program.
  • Monitor your network: Use network monitoring tools to detect and troubleshoot problems early.
  • Consider a router with good QoS (Quality of Service): QoS can prioritize network traffic, potentially improving DNS performance.
  • Use a wired connection when possible: Wired connections are generally more stable than Wi-Fi connections.
  • Avoid overloading your network: Too many devices using the internet simultaneously can strain your router and potentially cause DNS issues.

Conclusion

The “Can’t Reach DNS Server” error can be frustrating, but it’s usually solvable. By following the steps outlined in this comprehensive guide, from the simple to the advanced, you should be able to diagnose and fix the problem, restoring your internet access. Remember to start with the easiest solutions and work your way up, and don’t hesitate to contact your ISP or a qualified technician if you need further assistance. By understanding the basics of DNS and taking preventative measures, you can minimize the chances of encountering this error in the future.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top