AdAway's Missing Hosts: Why It Happens and How to Fix It

I recently stumbled upon a fascinating discussion regarding AdAway, a popular open-source ad blocker for Android. The core issue reported was that the application wasn't displaying the number of hosts being blocked, which is a key indicator of its effectiveness. This got me thinking about the potential reasons behind this problem and the troubleshooting steps users can take to resolve it.

Let's explore why AdAway might fail to display the number of hosts and how to get it back on track.

Understanding AdAway and Host Files

Before diving into the troubleshooting, it's crucial to understand how AdAway works. AdAway leverages the device's host file to block ads. The host file is a simple text file that maps hostnames (like example.com) to IP addresses. When AdAway is configured, it downloads or generates a host file containing entries that redirect ad-serving domains to 127.0.0.1 (localhost) or 0.0.0.0, effectively preventing the device from accessing those ad servers.

The number of hosts displayed in AdAway represents the number of entries in this host file. If this number isn't showing up, it indicates a problem with how AdAway is reading or processing the host file.

Potential Causes for the Missing Host Count

Several factors can contribute to AdAway not displaying the number of hosts. Here are some of the most common:

1. Root Access Issues

AdAway requires root access to modify the host file, which is located in the system partition. If root access isn't properly granted or if there are issues with the root implementation (e.g., a faulty Magisk module), AdAway won't be able to read or write to the host file, and the host count will be incorrect.

2. Corrupted Host File

The host file itself might be corrupted. This can happen due to various reasons, such as interrupted downloads, file system errors, or manual modifications gone wrong. A corrupted host file can prevent AdAway from parsing the entries correctly.

3. Incorrect Host File Location

AdAway expects the host file to be in a specific location (usually /system/etc/hosts). If the host file is located elsewhere or if there's a symbolic link pointing to the wrong file, AdAway won't be able to find and process it.

4. Insufficient Permissions

Even with root access, the host file might not have the correct permissions for AdAway to read it. The host file should typically have read permissions for all users (644 or rw-r--r--).

5. Conflicting Ad Blocking Solutions

Using multiple ad-blocking solutions simultaneously can lead to conflicts. For example, if another app is also modifying the host file or using a VPN to block ads, it can interfere with AdAway's operation.

6. Outdated AdAway Version

An outdated version of AdAway might contain bugs that prevent it from correctly reading the host file. Keeping AdAway updated is essential for ensuring compatibility and stability.

7. SELinux Issues

SELinux (Security-Enhanced Linux) is a security module in Android that can restrict the actions of apps, even with root access. If SELinux is enforcing strict policies, it might prevent AdAway from accessing the host file. While disabling SELinux is generally not recommended for security reasons, it can be a temporary troubleshooting step.

8. DNS Issues

While AdAway primarily relies on the host file, DNS settings can sometimes interfere. If the device is using a custom DNS server that bypasses the host file, ads might still be served, and AdAway's effectiveness will be reduced.

9. Storage Issues

In rare cases, storage-related issues, such as a full system partition or errors in the file system, can prevent AdAway from writing to the host file.

Troubleshooting Steps

Based on these potential causes, here's a systematic approach to troubleshooting AdAway's missing host count:

1. Verify Root Access

First and foremost, ensure that AdAway has proper root access. You can use a root checker app to confirm that root access is working correctly. If root access is not granted, try re-rooting your device or updating your rooting solution (e.g., Magisk).

2. Check Host File Integrity

Next, verify the integrity of the host file. You can do this by:

• Using a file manager with root access: Navigate to /system/etc/hosts and open the file with a text editor. Check for any obvious errors, such as corrupted characters or incomplete entries.
• Comparing with a known good host file: Download a fresh host file from a reputable source (like AdAway's default host file) and compare it with your current host file. If your host file is significantly different or contains errors, replace it with the known good version.
• Using AdAway's built-in update feature: AdAway has an option to update the host file from its default sources. This can help replace a corrupted host file with a fresh one.

3. Confirm Host File Location and Permissions

Ensure that the host file is located in the correct directory (/system/etc/hosts) and that it has the correct permissions (644 or rw-r--r--). You can use a file manager with root access to check and modify the permissions if necessary.

4. Disable Conflicting Ad Blocking Solutions

If you're using other ad-blocking apps or VPNs, temporarily disable them to see if they're interfering with AdAway. If disabling them resolves the issue, you might need to choose between the different solutions or configure them to work together without conflicts.

5. Update AdAway

Make sure you're using the latest version of AdAway. Check for updates on F-Droid or the AdAway website. Newer versions often contain bug fixes and improvements that can resolve compatibility issues.

6. Check SELinux Status (Advanced)

As a temporary troubleshooting step, you can check the SELinux status and, if necessary, set it to permissive. However, be aware that disabling SELinux can reduce the security of your device. Use this step with caution and re-enable SELinux after troubleshooting.

To check the SELinux status, you can use a terminal emulator and run the command getenforce. If it returns Enforcing, SELinux is enabled. To set it to permissive, run the command setenforce 0. To re-enable it, run setenforce 1.

7. Clear AdAway Data and Cache

Clearing AdAway's data and cache can sometimes resolve issues caused by corrupted settings or cached files. You can do this in the Android settings menu under Apps > AdAway > Storage > Clear Data and Clear Cache.

8. Reinstall AdAway

If none of the above steps work, try uninstalling and reinstalling AdAway. This can help ensure that you have a clean installation with the correct settings.

9. Check DNS Settings

Verify that your device is using the correct DNS settings. If you're using a custom DNS server, make sure it's not bypassing the host file. You can try switching to a public DNS server like Google DNS (8.8.8.8 and 8.8.4.4) or Cloudflare DNS (1.1.1.1) to see if it resolves the issue.

10. Check Storage Space

Ensure that your device has sufficient free storage space, especially in the system partition. If the system partition is full, AdAway might not be able to write to the host file.

Alternative Ad Blocking Solutions

If you've tried all the troubleshooting steps and still can't get AdAway to display the number of hosts correctly, it might be time to consider alternative ad-blocking solutions. Here are a few options:

1. Blokada

Blokada is another popular open-source ad blocker for Android. It uses a local VPN to filter traffic and block ads. Blokada doesn't require root access, making it a good alternative for non-rooted devices.

2. AdGuard for Android

AdGuard offers a comprehensive ad-blocking solution for Android, including a local VPN-based ad blocker and a DNS-based ad blocker. AdGuard also has a paid version with additional features.

3. DNS-Based Ad Blocking

As we discussed earlier, DNS-based ad blocking can be a very effective way to block ads on mobile devices. You can use a DNS service like NextDNS or AdGuard DNS to block ads at the network level.

4. Browser-Based Ad Blocking

If you primarily browse the web on your mobile device, you can use a browser with built-in ad blocking, such as Brave Browser, or install an ad-blocking extension in Firefox.

Integrating DNS-Based Blocking with AdAway (If Possible)

This got me thinking - could DNS-based blocking and AdAway complement each other? In theory, yes. AdAway is excellent at blocking ads from apps and specific domains. DNS-based solutions offer system-wide protection. Using both could create a layered approach. One could configure a custom DNS server on their Android device and then use AdAway with a smaller, more targeted host file. This could potentially reduce the load on AdAway and improve performance. However, this approach requires careful configuration to avoid conflicts.

My Recommendations by Use Case (Based on the AdAway Issue)

"I just want a reliable ad blocker that works without issues"

→ AdGuard DNS - Simple and effective, minimal configuration needed.

"I want to troubleshoot AdAway and get it working again"

→ Follow the troubleshooting steps above meticulously. Start with root access verification and host file integrity.

"I want a rootless ad blocking solution"

→ Blokada - Easy to set up and doesn't require root access.

"I want the most comprehensive ad blocking possible"

→ AdAway + AdGuard DNS - Use AdAway for app-based blocking and AdGuard DNS for system-wide protection.

What About Custom Host Files?

I've seen some users create custom host files with specific blocklists. This can be a powerful way to tailor your ad blocking to your specific needs. However, it also requires more technical knowledge and can be prone to errors. If you're considering using a custom host file, make sure you understand the format and syntax of the host file and that you're downloading the host file from a reputable source.

The Importance of Regular Updates

Regardless of which ad-blocking solution you choose, it's essential to keep it updated. Ad networks are constantly evolving their techniques to bypass ad blockers, so it's crucial to use an ad blocker that is regularly updated with the latest blocklists and techniques.

Final Thoughts

While AdAway's missing host count can be frustrating, it's usually a symptom of an underlying issue that can be resolved with careful troubleshooting. By following the steps outlined above, you should be able to get AdAway back on track or find an alternative ad-blocking solution that meets your needs.

Remember, effective ad blocking is an ongoing process. It requires vigilance, regular updates, and a willingness to adapt to the ever-changing landscape of online advertising. But the reward – a cleaner, faster, and more private mobile browsing experience – is well worth the effort.

Ready to explore other solutions? Check out my guide to the best ad blockers for mobile.