Update docs

docs/advanced-usage-zh.md

@@ -35,6 +35,8 @@
 
 你可以为特定的 IKEv2 客户端设置不同的 DNS 服务器。对于此用例，请参见 [#1562](https://github.com/hwdsl2/setup-ipsec-vpn/issues/1562#issuecomment-2151361658)。
 
+如果你的用例需要使用 IPTables 规则将 DNS 流量重定向到另一台服务器，请参见 [#1565](https://github.com/hwdsl2/setup-ipsec-vpn/issues/1565)。
+
 在某些情况下，你可能希望 VPN 客户端仅使用指定的 DNS 服务器来解析内部域名，并使用其本地配置的 DNS 服务器来解析所有其他域名。这可以使用 `modecfgdomains` 选项进行配置，例如 `modecfgdomains="internal.example.com, home"`。对于 IKEv2，将此选项添加到 `/etc/ipsec.d/ikev2.conf` 中的 `conn ikev2-cp` 小节。对于 IPsec/XAuth ("Cisco IPsec")，将此选项添加到 `/etc/ipsec.conf` 中的 `conn xauth-psk` 小节。然后运行 `service ipsec restart`。IPsec/L2TP 模式不支持此选项。
 
 ## 域名和更改服务器 IP

docs/advanced-usage.md

@@ -35,6 +35,8 @@ Advanced users can define `VPN_DNS_SRV1` and optionally `VPN_DNS_SRV2` when runn
 
 It is possible to set different DNS server(s) for specific IKEv2 client(s). For this use case, please refer to [#1562](https://github.com/hwdsl2/setup-ipsec-vpn/issues/1562#issuecomment-2151361658).
 
+If your use case requires redirecting DNS traffic to another server using IPTables rules, see [#1565](https://github.com/hwdsl2/setup-ipsec-vpn/issues/1565).
+
 In certain circumstances, you may want VPN clients to use the specified DNS server(s) only for resolving internal domain name(s), and use their locally configured DNS servers to resolve all other domain names. This can be configured using the `modecfgdomains` option, e.g. `modecfgdomains="internal.example.com, home"`. Add this option to section `conn ikev2-cp` in `/etc/ipsec.d/ikev2.conf` for IKEv2, and to section `conn xauth-psk` in `/etc/ipsec.conf` for IPsec/XAuth ("Cisco IPsec"). Then run `service ipsec restart`. IPsec/L2TP mode does not support this option.
 
 ## DNS name and server IP changes

docs/ikev2-howto-zh.md

@@ -577,6 +577,7 @@ sudo chmod 600 ca.cer client.cer client.key
 **另见：** [检查日志及 VPN 状态](clients-zh.md#检查日志及-vpn-状态)，[IKEv1 故障排除](clients-zh.md#ikev1-故障排除) 和 [高级用法](advanced-usage-zh.md)。
 
 * [无法连接到 VPN 服务器](#无法连接到-vpn-服务器)
+* [Ubuntu 20.04 无法导入客户端配置](#ubuntu-2004-无法导入客户端配置)
 * [macOS Sonoma 客户端重新连接](#macos-sonoma-客户端重新连接)
 * [无法连接多个 IKEv2 客户端](#无法连接多个-ikev2-客户端)
 * [IKE 身份验证凭证不可接受](#ike-身份验证凭证不可接受)
@@ -594,6 +595,12 @@ sudo chmod 600 ca.cer client.cer client.key
 
 [检查日志及 VPN 状态](clients-zh.md#检查日志及-vpn-状态)是否有错误。如果你遇到 retransmission 相关错误并且无法连接，说明 VPN 客户端和服务器之间的网络可能有问题。如果你从中国大陆进行连接，请考虑改用 IPsec VPN 以外的其他解决方案。
 
+### Ubuntu 20.04 无法导入客户端配置
+
+如果你在 2024-04-10 之前安装了 IPsec VPN，并且你的 VPN 服务器运行的是 Ubuntu Linux 版本 20.04，那么你可能会遇到无法在 iOS 或 macOS 设备上导入新生成的客户端配置文件 (`.mobileconfig`) 的问题，例如提示密码不正确。这可能是由 Ubuntu 20.04 上 libnss3 相关软件包的更新引起的，需要对 IKEv2 脚本进行一些更改 ([25670f3](https://github.com/hwdsl2/setup-ipsec-vpn/commit/25670f3))。
+
+要解决此问题，请首先按照[这些步骤](#更新-ikev2-辅助脚本)将服务器上的 IKEv2 脚本更新到最新版本。然后运行 `sudo ikev2.sh` 并选择 "export" 以重新创建客户端配置文件。
+
 ### macOS Sonoma 客户端重新连接
 
 macOS 14 (Sonoma) 存在[一个小问题](https://github.com/hwdsl2/setup-ipsec-vpn/issues/1486)，可能会导致 IKEv2 VPN 每 24-48 分钟断开并重新连接一次。其他 macOS 版本不受影响。首先[检查你的 macOS 版本](https://support.apple.com/zh-cn/HT201260)。要解决此问题，请按以下步骤操作。

docs/ikev2-howto.md

@@ -579,6 +579,7 @@ for the entire network, or use `192.168.0.10` for just one device, and so on.
 **See also:** [Check logs and VPN status](clients.md#check-logs-and-vpn-status), [IKEv1 troubleshooting](clients.md#ikev1-troubleshooting) and [Advanced usage](advanced-usage.md).
 
 * [Cannot connect to the VPN server](#cannot-connect-to-the-vpn-server)
+* [Ubuntu 20.04 cannot import client config](#ubuntu-2004-cannot-import-client-config)
 * [macOS Sonoma clients reconnect](#macos-sonoma-clients-reconnect)
 * [Unable to connect multiple IKEv2 clients](#unable-to-connect-multiple-ikev2-clients)
 * [IKE authentication credentials are unacceptable](#ike-authentication-credentials-are-unacceptable)
@@ -596,6 +597,12 @@ For servers with an external firewall (e.g. [EC2](https://docs.aws.amazon.com/AW
 
 [Check logs and VPN status](clients.md#check-logs-and-vpn-status) for errors. If you encounter retransmission related errors and are unable to connect, there may be network issues between the VPN client and server. If you are connecting from mainland China, consider switching to alternative solutions other than IPsec VPN.
 
+### Ubuntu 20.04 cannot import client config
+
+If you installed the IPsec VPN before 2024-04-10, and your VPN server runs Ubuntu Linux version 20.04, you may have encountered an issue where newly generated client configuration files (`.mobileconfig`) fail to import on iOS or macOS device(s) with errors like "incorrect password". This could be caused by updates to libnss3 related packages on Ubuntu 20.04, which required some changes ([25670f3](https://github.com/hwdsl2/setup-ipsec-vpn/commit/25670f3)) in the IKEv2 script.
+
+To fix this issue, first update the IKEv2 script on your server to the latest version using [these instructions](#update-ikev2-helper-script). After that, run `sudo ikev2.sh` and select "export" to re-create the client configuration files.
+
 ### macOS Sonoma clients reconnect
 
 macOS 14 (Sonoma) has [a minor issue](https://github.com/hwdsl2/setup-ipsec-vpn/issues/1486) that may cause IKEv2 VPN to disconnect and reconnect once every 24-48 minutes. Other macOS versions are not affected. First [check your macOS version](https://support.apple.com/en-us/HT201260). To work around this issue, follow the steps below.