Fixing Slow Internet on Ubuntu 24: Updating DNS with NetworkManager
🔍 Problem: Slow Internet on Ubuntu 24, but Works Fine on MacBook Pro
Recently, I faced an issue where the internet speed was slow and unreliable on my HP laptop running Ubuntu 24, but the same internet connection worked perfectly fine on my MacBook Pro.
Symptoms on Ubuntu 24 (HP Laptop)
- Websites took too long to load, especially GitHub, which either failed to open or loaded very slowly.
- Other websites sometimes worked, but performance was inconsistent.
- Speed tests showed normal internet speeds, but DNS resolution was slow.
MacBook Pro (Same Network, No Issues)
On my MacBook Pro, everything worked smoothly with no connectivity issues on the same Wi-Fi or mobile hotspot.
Suspected Issue
The issue wasn’t with the internet speed itself but rather with DNS resolution—meaning Ubuntu 24 was struggling to resolve website addresses quickly.
Upon further troubleshooting, I found that Ubuntu 24 does not use systemd-resolved by default. Instead, NetworkManager handles the DNS settings, so fixing it required configuring Google DNS through NetworkManager.
🛠️ Solution: Updating DNS Using NetworkManager
Since systemd-resolved is not available in Ubuntu 24, I directly configured Google DNS (8.8.8.8, 8.8.4.4) using NetworkManager.
🔧 Step 1: Identify Active Network Connection
First, I checked which network connection was active on my HP laptop (Ubuntu 24):
nmcli connection show --active
Example Output:
NAME UUID TYPE DEVICE
Wi-Fi 12345-abcde-67890-fghij wifi wlan0
Here, Wi-Fi is my active connection name.
🔧 Step 2: Update DNS to Google DNS (8.8.8.8, 8.8.4.4)
Next, I updated the DNS settings for my active connection using NetworkManager:
sudo nmcli connection modify "Wi-Fi" ipv4.dns "8.8.8.8 8.8.4.4"
sudo nmcli connection modify "Wi-Fi" ipv4.ignore-auto-dns yes
This forces Ubuntu to bypass the default ISP-provided DNS and use Google DNS instead.
🔧 Step 3: Restart Network Connection
To apply the new DNS settings, I restarted the network:
sudo nmcli connection down "Wi-Fi" && sudo nmcli connection up "Wi-Fi"
âś… Step 4: Verify the New DNS Settings
To ensure the DNS update was successful, I checked the DNS settings again:
nmcli device show | grep IP4.DNS
Expected Output:
IP4.DNS[1]: 8.8.8.8
IP4.DNS[2]: 8.8.4.4
This confirms that Ubuntu is now using Google’s DNS servers.
🛠️ Step 5: Testing DNS Resolution & Speed
After applying the fix, I performed a DNS lookup test to verify that Ubuntu was using Google DNS properly:
dig google.com
Output (Success âś…):
;; SERVER: 8.8.8.8#53(8.8.8.8) (UDP)
This confirms that all DNS queries are now being resolved by Google DNS, rather than the slow ISP-provided DNS.
🚀 Results & Improvements
- âś… GitHub and other websites now load instantly without delays or failures.
- âś… Overall internet performance on Ubuntu 24 significantly improved.
- âś… MacBook Pro and HP laptop now have similar browsing speeds.
đź’ˇ Conclusion
If you’re facing slow internet on Ubuntu 24—especially with websites like GitHub failing to load—it could be a DNS resolution issue rather than a speed problem.
Since Ubuntu 24 does not use systemd-resolved, the best way to fix it is to update DNS settings through NetworkManager and set it to Google DNS (8.8.8.8, 8.8.4.4).
This method ensures a faster, more stable, and reliable browsing experience on Ubuntu.
🔹 Additional Notes
- If you are using a VPN, make sure it doesn’t override your DNS settings.
- If the issue persists, you can try disabling IPv6:
sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1