什麼是VPN伺服器？
ChatGPT：
VPN伺服器（Virtual Private Network Server）是一種讓用戶能夠通過公共網路（如互聯網）安全地連接到私人網路的技術。簡單來說，VPN伺服器允許用戶在不安全的網路上建立一個安全、加密的連接，從而保護數據傳輸的隱私和安全。
以下是VPN伺服器的一些關鍵特點：
1. **安全性：** VPN通過加密技術保護用戶的網絡流量，防止數據被竊取或篡改。這對於使用公共Wi-Fi等不安全網路時特別重要。
2. **隱私保護：** 使用VPN時，用戶的真實IP地址被隱藏，從而保護了用戶的網絡身份和隱私。
3. **遠程訪問：** VPN允許員工安全地遠程訪問公司的私人網路，即使他們身處世界任何地方。
4. **繞過地理限制：** 通過連接到位於不同國家或地區的VPN伺服器，用戶可以訪問那些在其實際地理位置上被限制或封鎖的網站和服務。
5. **網絡管理：** 對於企業而言，VPN伺服器可以幫助管理員監控和控制網絡訪問，確保公司政策和安全標準得到遵守。
總的來說，VPN伺服器在當今網絡環境中提供了一個重要的安全和隱私工具，無論是對於個人用戶還是企業用戶。
VPN伺服器非常好用，千萬不要認爲只是翻牆用，而我也沒有什麼牆要翻。簡而言之，VPN伺服器使得我辦公室內部網路跟着我走到天涯海角。我在世界上的每一個角落，只要連得上Internet，存取辦公室內部的電腦，和在辦公室裏一樣，而且非常安全鞏固。
架設VPN伺服器，利用ChatGPT除錯
但是架設VPN伺服器非常複雜，尤其我不是這個領域的人，對各種加密、解密技術很陌生。碰到錯誤時往往要花掉很多時間去爬文解決。
總算過關斬將，最後臨門一腳，還是沒連成功。面對排山倒海的系統事件訊息，總算看到了一個比較相關的錯誤訊息，不管三七二十一，丟進ChatGPT的Promt裏：
ovpn-server:
PUSH: No common cipher between server and client.
Server data-ciphers: 'AES-256-GCM:AES-128-GCM:CHACHA20-POLY1305',
client supported ciphers 'AES-256-CBC'
ChatGPT：
The error message you’re encountering, “PUSH: No common cipher between server and client,” indicates a mismatch in the encryption ciphers supported by the OpenVPN server and the client. In simpler terms, the server and client are unable to establish a secure connection because they don’t have a common language for encryption.
Here’s a breakdown of the situation:
1. **Server Supported Ciphers:** Your server is configured to use the following data ciphers: ‘AES-256-GCM’, ‘AES-128-GCM’, and ‘CHACHA20-POLY1305’. These are relatively modern and secure ciphers.
2. **Client Supported Cipher:** The client, however, supports ‘AES-256-CBC’, which is not on the list of ciphers supported by the server.
To resolve this issue, you have a couple of options:
1. **Update the Client Configuration:** Modify the client configuration to support one of the ciphers that the server supports. This is the recommended approach as the ciphers supported by your server are more modern and generally considered more secure. For example, you could update the client configuration to use ‘AES-256-GCM’.
2. **Update the Server Configuration:** Alternatively, you could add ‘AES-256-CBC’ to the list of supported ciphers on the server. However, this is less desirable because ‘AES-256-CBC’ is older and not as secure as the ciphers currently supported by your server.
Here’s an example of how you might update the client configuration file (client.ovpn) to use ‘AES-256-GCM’:
“`
cipher AES-256-GCM
“`
Remember to ensure that both the server and client configurations are compatible in terms of encryption ciphers to establish a successful VPN connection. Always consider security implications when making changes to encryption settings.
按照ChatGPT的建議，問題立刻解決。大爽。