Update docs

[ci skip]

README-zh.md

@@ -52,7 +52,9 @@
 这也包括各种云计算服务中的 Linux 虚拟机，比如 Google Compute Engine, Amazon EC2, Microsoft Azure, IBM SoftLayer, VMware vCloud Air, Rackspace, DigitalOcean, Vultr 和 Linode。
 
 <a href="azure/README-zh.md" target="_blank">
-    <img src="http://azuredeploy.net/deploybutton.png" alt="Deploy to Azure" />
+    <img src="docs/images/azure-deploy-button.png" alt="Deploy to Azure" />
+</a> <a href="http://dovpn.carlfriess.com/" target="_blank">
+    <img src="docs/images/do-install-button.png" alt="Install on DigitalOcean" />
 </a>
 
 <a href="https://blog.ls20.com/ipsec-l2tp-vpn-auto-setup-for-ubuntu-12-04-on-amazon-ec2/#gettingavps" target="_blank">**&raquo; 我想建立并使用自己的 VPN ，但是没有可用的服务器**</a>

README.md

@@ -52,7 +52,9 @@ A dedicated server or Virtual Private Server (VPS), freshly installed with one o
 This also includes Linux VMs in public clouds such as Google Compute Engine, Amazon EC2, Microsoft Azure, IBM SoftLayer, VMware vCloud Air, Rackspace, DigitalOcean, Vultr and Linode.
 
 <a href="azure/README.md" target="_blank">
-    <img src="http://azuredeploy.net/deploybutton.png" alt="Deploy to Azure" />
+    <img src="docs/images/azure-deploy-button.png" alt="Deploy to Azure" />
+</a> <a href="http://dovpn.carlfriess.com/" target="_blank">
+    <img src="docs/images/do-install-button.png" alt="Install on DigitalOcean" />
 </a>
 
 <a href="https://blog.ls20.com/ipsec-l2tp-vpn-auto-setup-for-ubuntu-12-04-on-amazon-ec2/#gettingavps" target="_blank">**&raquo; I want to run my own VPN but don't have a server for that**</a>
@@ -93,7 +95,7 @@ VPN_USER='your_vpn_username' \
 VPN_PASSWORD='your_vpn_password' sh vpnsetup.sh
 ```
 
-For installation on DigitalOcean, check out this <a href="https://usefulpcguide.com/17318/create-your-own-vpn/" target="_blank">step-by-step guide</a> by Tony Tran.
+For install on DigitalOcean, you may refer to this <a href="https://usefulpcguide.com/17318/create-your-own-vpn/" target="_blank">step-by-step guide</a> by Tony Tran.
 
 **Note:** If unable to download via `wget`, you may also open <a href="vpnsetup.sh" target="_blank">vpnsetup.sh</a> (or <a href="vpnsetup_centos.sh" target="_blank">vpnsetup_centos.sh</a>) and click the **`Raw`** button. Press `Ctrl-A` to select all, `Ctrl-C` to copy, then paste into your favorite editor.
 

azure/README-zh.md

@@ -15,7 +15,7 @@
 请点击以下按钮开始：
 
 <a href="https://portal.azure.com/#create/Microsoft.Template/uri/https%3A%2F%2Fraw.githubusercontent.com%2Fhwdsl2%2Fsetup-ipsec-vpn%2Fmaster%2Fazure%2Fazuredeploy.json" target="_blank">
-    <img src="http://azuredeploy.net/deploybutton.png" alt="Deploy to Azure" />
+    <img src="../docs/images/azure-deploy-button.png" alt="Deploy to Azure" />
 </a>
 
 屏幕截图：

azure/README.md

@@ -15,7 +15,7 @@ Customizable with the following options:
 Press this button to start:
 
 <a href="https://portal.azure.com/#create/Microsoft.Template/uri/https%3A%2F%2Fraw.githubusercontent.com%2Fhwdsl2%2Fsetup-ipsec-vpn%2Fmaster%2Fazure%2Fazuredeploy.json" target="_blank">
-    <img src="http://azuredeploy.net/deploybutton.png" alt="Deploy to Azure" />
+    <img src="../docs/images/azure-deploy-button.png" alt="Deploy to Azure" />
 </a>
 
 Screenshot:

docs/clients-zh.md

@@ -160,7 +160,14 @@ VPN 连接成功后，网络状态图标上会出现 VPN 指示。最后你可
 
 1. 在文件 `xl2tpd.conf` 中，删除这一行 `# your vpn server goes here`。
 1. 在文件 `options.l2tpd.client` 中，将 `require-mschap-v2` 换成 `require-chap`。
+1. 替换 `sudo echo "c XXX-YOUR-CONNECTION-NAME-XXX <user> <pass>" > /var/run/xl2tpd/l2tp-control` 为:
+
+   ```
+   echo "c XXX-YOUR-CONNECTION-NAME-XXX <user> <pass>" | sudo tee /var/run/xl2tpd/l2tp-control
+   ```
+
 1. 替换最后一个命令 `sudo route add -net default gw <vpn server local ip>` 为：
+
    ```
    sudo route add default dev ppp0
    ```
@@ -211,7 +218,7 @@ sudo route del default dev ppp0
 1. 单击 **允许使用这些协议**。选中 "质询握手身份验证协议 (CHAP)" 复选框，并且取消选中所有其它项。
 1. 单击 **确定** 保存 VPN 连接的详细信息。
 
-![Select only CHAP in VPN connection properties-2](https://cloud.githubusercontent.com/assets/5104323/16026263/cbda945a-3192-11e6-96a6-ff18c5dd9a48.png)
+![Select CHAP in VPN connection properties](images/vpn-properties-zh.png)
 
 ### 其它错误
 

docs/clients.md

@@ -160,7 +160,14 @@ Follow the steps in <a href="http://www.jasonernst.com/2016/06/21/l2tp-ipsec-vpn
 
 1. In `xl2tpd.conf`, remove the line `# your vpn server goes here`. 
 1. In `options.l2tpd.client`, replace `require-mschap-v2` with `require-chap`.
+1. Replace `sudo echo "c XXX-YOUR-CONNECTION-NAME-XXX <user> <pass>" > /var/run/xl2tpd/l2tp-control` with:
+
+   ```
+   echo "c XXX-YOUR-CONNECTION-NAME-XXX <user> <pass>" | sudo tee /var/run/xl2tpd/l2tp-control
+   ```
+
 1. Replace the last command `sudo route add -net default gw <vpn server local ip>` with:
+
    ```
    sudo route add default dev ppp0
    ```
@@ -211,7 +218,7 @@ To fix this error, please follow these steps:
 1. Click **Allow these protocols**. Check "Challenge Handshake Authentication Protocol (CHAP)" and uncheck all others.
 1. Click **OK** to save the VPN connection details.
 
-![Select only CHAP in VPN connection properties](https://cloud.githubusercontent.com/assets/5104323/16024310/b113e9b6-3186-11e6-9e03-12f5455487ba.png)
+![Select CHAP in VPN connection properties](images/vpn-properties.png)
 
 ### Other Errors