---
title: Thunderbird
description: 
---

Thunderbird is known to have trouble detecting when a proxy should be used. It can be useful to force Thunderbird to **always** use a proxy or to force it to **never** use a proxy.

In some cases it may be sufficient to use the **IPv6 work-around** only.

AUTOMATIC_TABLE_OF_CONTENTS

## Always use proxy

This will work for any normal e-mail provider, including Gmail in China. Note: these instructions apply to **WEB** mode in VPNGUI only. *Do not use for any other VPN method.*

Open the Thunderbird **Preferences/Settings**, select **Advanced**, select **Network & Disk Space**, then choose **Settings..**

![screenshot](/media/6/Screen-Shot-2018-03-03-at-09.36.49-1024x1010.png)

Enable **Manual proxy configuration**. Enter **127.0.0.1** for **HTTP Proxy**, **16005** for **Port**. Enable the **Use this proxy for all protocols** option. Confirm by selecting **OK**.

![screenshot](/media/7/Screen-Shot-2018-03-03-at-09.37.29-1024x1010.png)

Make sure VPNGUI is connected in **WEB** mode. (No need to choose the GMAIL mode.) Then restart Thunderbird.

## Never use proxy

This will work for any e-mail provider which is not blocked. (Do not use for Gmail in China.)

Open the Thunderbird **Preferences/Settings**, select **Advanced**, select **Network & Disk Space**, then choose **Settings..**

![screenshot](/media/6/Screen-Shot-2018-03-03-at-09.36.49-1024x1010.png)

Select the **No Proxy** option. Confirm by selecting **OK**. The restart Thunderbird.

![screenshot](/media/8/Screen-Shot-2018-03-03-at-09.53.40-1024x1011.png)

## Restore defaults

If you stop using VPNGUI, or if you use VPNGUI in OpenVPN/StealthVPN mode, you may wish to restore Thunderbird to its default settings:

Open the Thunderbird **Preferences/Settings**, select **Advanced**, select **Network & Disk Space**, then choose **Settings..**

![screenshot](/media/6/Screen-Shot-2018-03-03-at-09.36.49-1024x1010.png)

Select the **Use system proxy settings** option. Confirm by selecting **OK**. The restart Thunderbird.

![screenshot](/media/9/Screen-Shot-2018-03-03-at-09.53.43-1024x1011.png)

## IPv6 work-around

If you're on an IPv6 network and choose a VPN server without IPv6, this can cause problems. You can work-around the issue by disabling IPv6 DNS in Thunderbird.

Open the Thunderbird **Preferences/Settings**, select **Advanced**, select **General**, then choose **Config Editor..**

![screenshot](/media/11/Screen-Shot-2018-03-03-at-10.00.35-1024x1011.png)

Confirm that you accept the risks.

![screenshot](/media/12/Screen-Shot-2018-03-03-at-10.00.39-1024x727.png)

Search for the **network.dns.disableIPv6** option and switch it to **true**. (You can switch it by simply double-clicking it.)

*Please do **NOT** change any other parameters.*

![screenshot](/media/10/Screen-Shot-2018-03-03-at-10.00.51-1024x727.png)

Restart Thunderbird to apply the change.