Update docs

- Closes #433

README-zh.md

@@ -143,7 +143,7 @@ VPN_PASSWORD='你的VPN密码' sh vpnsetup.sh
 
 同一个 VPN 账户可以在你的多个设备上使用。但是由于 IPsec/L2TP 的局限性，如果需要同时连接在同一个 NAT （比如家用路由器）后面的多个设备到 VPN 服务器，你必须仅使用 <a href="docs/clients-xauth-zh.md" target="_blank">IPsec/XAuth 模式</a>。
 
-对于有外部防火墙的服务器（比如 <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-network-security.html" target="_blank">EC2</a>/<a href="https://cloud.google.com/vpc/docs/firewalls" target="_blank">GCE</a>），请为 VPN 打开 UDP 端口 500 和 4500。
+对于有外部防火墙的服务器（比如 <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-network-security.html" target="_blank">EC2</a>/<a href="https://cloud.google.com/vpc/docs/firewalls" target="_blank">GCE</a>），请为 VPN 打开 UDP 端口 500 和 4500。阿里云用户请参见 [#433](https://github.com/hwdsl2/setup-ipsec-vpn/issues/433)。
 
 如果需要添加，修改或者删除 VPN 用户账户，请参见 <a href="docs/manage-users-zh.md" target="_blank">管理 VPN 用户</a>。
 
@@ -168,6 +168,8 @@ wget https://git.io/vpnupgrade -O vpnupgrade.sh
 wget https://git.io/vpnupgrade-centos -O vpnupgrade.sh
 ```
 
+:warning: VPN 脚本默认安装 Libreswan 3.22，因为新版本 3.23 和 3.25 存在问题，从而不能同时连接在同一个 NAT （比如家用路由器）后面的多个 IPsec/XAuth VPN 客户端。
+
 ## 问题和反馈
 
 - 有问题需要提问？请先搜索已有的留言，在 <a href="https://gist.github.com/hwdsl2/9030462#comments" target="_blank">这个 Gist</a> 以及 <a href="https://blog.ls20.com/ipsec-l2tp-vpn-auto-setup-for-ubuntu-12-04-on-amazon-ec2/#disqus_thread" target="_blank">我的博客</a>。

README.md

@@ -143,7 +143,7 @@ For **Windows users**, this <a href="docs/clients.md#windows-error-809" target="
 
 The same VPN account can be used by your multiple devices. However, due to an IPsec/L2TP limitation, if you wish to connect multiple devices simultaneously from behind the same NAT (e.g. home router), you must use only <a href="docs/clients-xauth.md" target="_blank">IPsec/XAuth mode</a>.
 
-For servers with an external firewall (e.g. <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-network-security.html" target="_blank">EC2</a>/<a href="https://cloud.google.com/vpc/docs/firewalls" target="_blank">GCE</a>), open UDP ports 500 and 4500 for the VPN.
+For servers with an external firewall (e.g. <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-network-security.html" target="_blank">EC2</a>/<a href="https://cloud.google.com/vpc/docs/firewalls" target="_blank">GCE</a>), open UDP ports 500 and 4500 for the VPN. Aliyun users, see [#433](https://github.com/hwdsl2/setup-ipsec-vpn/issues/433).
 
 If you wish to add, edit or remove VPN user accounts, see <a href="docs/manage-users.md" target="_blank">Manage VPN Users</a>.
 
@@ -168,6 +168,8 @@ wget https://git.io/vpnupgrade -O vpnupgrade.sh
 wget https://git.io/vpnupgrade-centos -O vpnupgrade.sh
 ```
 
+:warning: The VPN scripts install Libreswan 3.22 by default, because newer versions 3.23 and 3.25 have issues with connecting multiple IPsec/XAuth VPN clients from behind the same NAT (e.g. home router).
+
 ## Bugs & Questions
 
 - Got a question? Please first search other people's comments <a href="https://gist.github.com/hwdsl2/9030462#comments" target="_blank">in this Gist</a> and <a href="https://blog.ls20.com/ipsec-l2tp-vpn-auto-setup-for-ubuntu-12-04-on-amazon-ec2/#disqus_thread" target="_blank">on my blog</a>.

docs/ikev2-howto-zh.md

@@ -204,7 +204,7 @@ Libreswan 支持通过使用 RSA 签名算法的 X.509 Machine Certificates 来
    1. 启用新的 IKEv2 VPN 连接，并且开始使用 VPN！   
       https://wiki.strongswan.org/projects/strongswan/wiki/Win7Connect
 
-   1. （可选步骤） 如需启用更安全的加密方式，可以添加 <a href="https://wiki.strongswan.org/projects/strongswan/wiki/Windows7#AES-256-CBC-and-MODP2048" target="_blank">这个注册表键</a> 并重启。
+   1. （可选步骤） 如需启用更安全的加密方式，可以添加 <a href="https://wiki.strongswan.org/projects/strongswan/wiki/WindowsClients#AES-256-CBC-and-MODP2048" target="_blank">这个注册表键</a> 并重启。
 
 1. 连接成功后，你可以到 <a href="https://www.ipchicken.com" target="_blank">这里</a> 检测你的 IP 地址，应该显示为`你的 VPN 服务器 IP`。
 
@@ -217,4 +217,4 @@ Windows 自带的 VPN 客户端不支持 IKEv2 fragmentation。在有些网络
 * https://libreswan.org/wiki/VPN_server_for_remote_clients_using_IKEv2
 * https://libreswan.org/wiki/HOWTO:_Using_NSS_with_libreswan
 * https://libreswan.org/man/ipsec.conf.5.html
-* https://wiki.strongswan.org/projects/strongswan/wiki/Windows7
+* https://wiki.strongswan.org/projects/strongswan/wiki/WindowsClients

docs/ikev2-howto.md

@@ -204,7 +204,7 @@ Before continuing, make sure you have successfully <a href="https://github.com/h
    1. Start the new IKEv2 VPN connection, and enjoy your VPN!   
       https://wiki.strongswan.org/projects/strongswan/wiki/Win7Connect
 
-   1. (Optional) You may enable stronger ciphers by adding <a href="https://wiki.strongswan.org/projects/strongswan/wiki/Windows7#AES-256-CBC-and-MODP2048" target="_blank">this registry key</a> and reboot.
+   1. (Optional) You may enable stronger ciphers by adding <a href="https://wiki.strongswan.org/projects/strongswan/wiki/WindowsClients#AES-256-CBC-and-MODP2048" target="_blank">this registry key</a> and reboot.
 
 1. Once successfully connected, you can verify that your traffic is being routed properly by <a href="https://www.google.com/search?q=my+ip" target="_blank">looking up your IP address on Google</a>. It should say "Your public IP address is `Your VPN Server IP`".
 
@@ -217,4 +217,4 @@ The built-in VPN client in Windows does not support IKEv2 fragmentation. On some
 * https://libreswan.org/wiki/VPN_server_for_remote_clients_using_IKEv2
 * https://libreswan.org/wiki/HOWTO:_Using_NSS_with_libreswan
 * https://libreswan.org/man/ipsec.conf.5.html
-* https://wiki.strongswan.org/projects/strongswan/wiki/Windows7
+* https://wiki.strongswan.org/projects/strongswan/wiki/WindowsClients