Fix: Tailscale On IPhone Only Works On WiFi

Hey guys,

Are you experiencing issues with Tailscale on your iPhone, where it connects perfectly fine on WiFi but just times out when you switch to cellular data? You're not alone! Many users have encountered this frustrating problem, but don't worry, we're here to help you troubleshoot and get your Tailscale working smoothly on both WiFi and cellular.

Understanding the Issue

Before we dive into the solutions, let's understand why this might be happening. Tailscale creates a secure, private network using WireGuard, allowing you to access your devices and services remotely. When your iPhone is on WiFi, it typically has a stable and unrestricted internet connection. However, cellular networks can be more complex, with various factors potentially interfering with Tailscale's connection.

Cellular networks often use Network Address Translation (NAT) and firewalls, which can block or disrupt the UDP traffic that Tailscale relies on. Additionally, some mobile carriers might implement traffic shaping or other policies that affect VPN connections. These interferences can lead to the "connects" but times out behavior you're seeing.

Moreover, iOS's power-saving features can sometimes suspend or throttle background processes, including Tailscale, when on cellular data to conserve battery life. This can result in dropped connections or timeouts. Misconfigured APN (Access Point Name) settings can also cause problems, as they control how your iPhone connects to the cellular network.

Troubleshooting Steps

Now that we have a better understanding of the potential causes, let's go through some troubleshooting steps to resolve the issue. Follow these steps in order, testing Tailscale after each one to see if the problem is fixed.

1. Check Cellular Data Settings

The first thing you should do is ensure that Tailscale has permission to use cellular data. Here’s how:

1. Open the Settings app on your iPhone.
2. Scroll down and tap on Cellular.
3. Find Tailscale in the list of apps.
4. Make sure the toggle next to Tailscale is turned on (green). If it’s off, Tailscale won’t be able to use cellular data, which would explain why it only works on WiFi.

While you’re in the Cellular settings, also check the Cellular Data Options. Ensure that Low Data Mode is turned off, as this can restrict background data usage and interfere with Tailscale's connection. To do this, tap on Cellular Data Options and toggle off Low Data Mode if it’s enabled.

2. Restart Tailscale and Your iPhone

Sometimes, a simple restart can resolve temporary glitches that might be causing the problem. First, close the Tailscale app completely:

1. Open the App Switcher by swiping up from the bottom of the screen (or double-pressing the Home button on older iPhones).
2. Find the Tailscale app.
3. Swipe up on the Tailscale app to close it.

Next, restart your iPhone:

1. Press and hold either the volume button and the side button (or the top button on older iPhones) until the power-off slider appears.
2. Drag the slider to turn off your iPhone.
3. Wait a few seconds, then press and hold the side button (or the top button) again until you see the Apple logo.

Once your iPhone has restarted, open Tailscale and check if it now connects on cellular data.

3. Check and Reset Network Settings

Your iPhone’s network settings might be misconfigured, causing issues with cellular data connections. To resolve this, you can try resetting your network settings. Keep in mind that this will also reset your WiFi passwords, so you’ll need to re-enter them.

1. Open the Settings app on your iPhone.
2. Tap on General.
3. Scroll down and tap on Transfer or Reset iPhone.
4. Tap on Reset.
5. Choose Reset Network Settings.
6. Enter your passcode if prompted.

After resetting your network settings, reconnect to your WiFi network and test Tailscale on cellular data again.

4. Disable WiFi Assist

WiFi Assist is a feature that automatically switches your iPhone to cellular data when the WiFi signal is weak. While this can be helpful in some situations, it can also interfere with Tailscale's connection. To disable WiFi Assist:

1. Open the Settings app on your iPhone.
2. Tap on Cellular.
3. Scroll down to the bottom and turn off WiFi Assist.

With WiFi Assist disabled, your iPhone will stay connected to WiFi even if the signal is weak, which might help stabilize Tailscale's connection.

5. Update Tailscale and iOS

Using outdated software can sometimes cause compatibility issues. Make sure you’re running the latest versions of both Tailscale and iOS.

To update Tailscale:

1. Open the App Store on your iPhone.
2. Tap on your profile icon in the top right corner.
3. Scroll down to see if there’s an update available for Tailscale. If there is, tap Update.

To update iOS:

1. Open the Settings app on your iPhone.
2. Tap on General.
3. Tap on Software Update.
4. If there’s an update available, tap Download and Install.

Keeping your software up to date ensures that you have the latest bug fixes and improvements, which can resolve connectivity issues.

6. Check APN Settings

APN (Access Point Name) settings are used to configure your iPhone’s connection to the cellular network. Incorrect APN settings can prevent Tailscale from connecting on cellular data. You can usually find the correct APN settings for your mobile carrier on their website or by contacting their customer support.

To check and modify your APN settings:

1. Open the Settings app on your iPhone.
2. Tap on Cellular.
3. Tap on Cellular Data Network.
4. Enter the correct APN settings for your carrier. The settings usually include APN, Username, and Password. If you’re not sure what the correct settings are, contact your carrier for assistance.

7. Disable iCloud Private Relay

iCloud Private Relay is a feature that encrypts your internet traffic and hides your IP address from websites and network providers. While this enhances privacy, it can sometimes interfere with VPN connections like Tailscale. To disable iCloud Private Relay:

1. Open the Settings app on your iPhone.
2. Tap on your name at the top.
3. Tap on iCloud.
4. Tap on Private Relay.
5. Turn off Private Relay.

After disabling iCloud Private Relay, check if Tailscale now connects on cellular data.

8. Test with a Different Cellular Network

In some cases, the issue might be specific to your mobile carrier or network configuration. Try using your iPhone with a different SIM card or on a different cellular network to see if Tailscale works. This can help you determine if the problem lies with your carrier.

Advanced Troubleshooting

If the above steps haven't resolved the issue, here are some more advanced troubleshooting steps you can try.

1. Check Tailscale Logs

Tailscale logs can provide valuable information about what’s going wrong with the connection. To access Tailscale logs on your iPhone:

1. Open the Tailscale app.
2. Tap on the three horizontal lines in the top left corner.
3. Tap on Settings.
4. Scroll down and tap on Diagnostics.
5. Tap on View Logs.

Examine the logs for any error messages or clues that might indicate the cause of the problem. You can also share these logs with Tailscale support for further assistance.

2. Use a Custom DNS Server

Sometimes, using a custom DNS server can improve connectivity. You can configure your iPhone to use a custom DNS server in the WiFi and cellular settings.

1. Open the Settings app on your iPhone.
2. Tap on WiFi and select your network.
3. Tap on Configure DNS and choose Manual.
4. Add a custom DNS server, such as 8.8.8.8 (Google DNS) or 1.1.1.1 (Cloudflare DNS).
5. Go back to Settings and tap on Cellular.
6. Tap on Cellular Data Options.
7. Tap on DNS and add the same custom DNS server.

Using a custom DNS server can sometimes bypass network restrictions or improve DNS resolution, which might help Tailscale connect on cellular data.

3. Contact Tailscale Support

If you’ve tried all the troubleshooting steps and Tailscale still doesn’t work on cellular data, it’s time to contact Tailscale support. They can provide more specific guidance and help you diagnose the issue further.

Conclusion

Having Tailscale working seamlessly on both WiFi and cellular data is crucial for remote access and secure networking. By following the troubleshooting steps outlined in this guide, you should be able to resolve the "connects" but times out issue and enjoy a stable Tailscale connection on your iPhone. Remember to check your cellular data settings, restart your devices, reset network settings, and keep your software up to date. Good luck, and happy networking!