diff --git a/README-zh.md b/README-zh.md
index d5d2555..f74746e 100644
--- a/README-zh.md
+++ b/README-zh.md
@@ -152,7 +152,7 @@ VPN_PASSWORD='你的VPN密码' sh vpnsetup.sh
 
 在 VPN 已连接时，客户端配置为使用 <a href="https://developers.google.com/speed/public-dns/" target="_blank">Google Public DNS</a>。如果偏好其它的域名解析服务，请编辑 `/etc/ppp/options.xl2tpd` 和 `/etc/ipsec.conf` 并替换 `8.8.8.8` 和 `8.8.4.4`。然后重启服务器。
 
-使用内核支持有助于提高 IPsec/L2TP 性能。它在以下系统上可用： Ubuntu 18.04/16.04, Debian 9 和 CentOS 7/6。 Ubuntu 用户需要安装 `` linux-image-extra-`uname -r` `` 软件包并运行 `service xl2tpd restart`。
+使用内核支持有助于提高 IPsec/L2TP 性能。它在以下系统上可用： Ubuntu 18.04/16.04, Debian 9 和 CentOS 7/6. Ubuntu 系统需要安装 `linux-modules-extra-$(uname -r)`（或者 `linux-image-extra`），然后运行 `service xl2tpd restart`。
 
 如果需要在安装后更改 IPTables 规则，请编辑 `/etc/iptables.rules` 和/或 `/etc/iptables/rules.v4` (Ubuntu/Debian)，或者 `/etc/sysconfig/iptables` (CentOS/RHEL)。然后重启服务器。
 
diff --git a/README.md b/README.md
index 0de60e6..00dd414 100644
--- a/README.md
+++ b/README.md
@@ -152,7 +152,7 @@ If you wish to add, edit or remove VPN user accounts, see <a href="docs/manage-u
 
 Clients are set to use <a href="https://developers.google.com/speed/public-dns/" target="_blank">Google Public DNS</a> when the VPN is active. If another DNS provider is preferred, replace `8.8.8.8` and `8.8.4.4` in both `/etc/ppp/options.xl2tpd` and `/etc/ipsec.conf`. Then reboot your server.
 
-Using kernel support could improve IPsec/L2TP performance. It is available on Ubuntu 18.04/16.04, Debian 9 and CentOS 7/6. Ubuntu users need to install the `` linux-image-extra-`uname -r` `` package and run `service xl2tpd restart`.
+Using kernel support could improve IPsec/L2TP performance. It is available on Ubuntu 18.04/16.04, Debian 9 and CentOS 7/6. Ubuntu users: Install `linux-modules-extra-$(uname -r)` (or `linux-image-extra`), then run `service xl2tpd restart`.
 
 To modify the IPTables rules after install, edit `/etc/iptables.rules` and/or `/etc/iptables/rules.v4` (Ubuntu/Debian), or `/etc/sysconfig/iptables` (CentOS/RHEL). Then reboot your server.
 
diff --git a/docs/clients-zh.md b/docs/clients-zh.md
index 1e26b28..2db647c 100644
--- a/docs/clients-zh.md
+++ b/docs/clients-zh.md
@@ -190,6 +190,16 @@ Windows Phone 8.1 及以上版本用户可以尝试按照 <a href="http://forums
 
 *其他语言版本: [English](clients.md#troubleshooting), [简体中文](clients-zh.md#故障排除).*
 
+* [Windows 错误 809](#windows-错误-809)
+* [Windows 错误 628](#windows-错误-628)
+* [Windows 10 升级](#windows-10-升级)
+* [Windows 8/10 DNS 泄漏](#windows-810-dns-泄漏)
+* [macOS VPN 流量](#macos-vpn-流量)
+* [Android 6 及以上版本](#android-6-及以上版本)
+* [Chromebook 连接问题](#chromebook-连接问题)
+* [其它错误](#其它错误)
+* [额外的步骤](#额外的步骤)
+
 ### Windows 错误 809
 
 > 无法建立计算机与 VPN 服务器之间的网络连接，因为远程服务器未响应。
diff --git a/docs/clients.md b/docs/clients.md
index fc5b73c..39679f2 100644
--- a/docs/clients.md
+++ b/docs/clients.md
@@ -190,6 +190,16 @@ See [Linux VPN Clients](#linux-vpn-clients).
 
 *Read this in other languages: [English](clients.md#troubleshooting), [简体中文](clients-zh.md#故障排除).*
 
+* [Windows Error 809](#windows-error-809)
+* [Windows Error 628](#windows-error-628)
+* [Windows 10 upgrades](#windows-10-upgrades)
+* [Windows 8/10 DNS leaks](#windows-810-dns-leaks)
+* [macOS VPN traffic](#macos-vpn-traffic)
+* [Android 6 and above](#android-6-and-above)
+* [Chromebook issues](#chromebook-issues)
+* [Other errors](#other-errors)
+* [Additional steps](#additional-steps)
+
 ### Windows Error 809
 
 > The network connection between your computer and the VPN server could not be established because the remote server is not responding.