Linux 遠端登入ssh與telnet
阿新 • • 發佈：2018-12-25
Linux 遠端登入ssh與telnet
telnet伺服器和域名系統的埠號
[email protected]:/# grep telnet /etc/services
telnet 23/tcp
rtelnet 107/tcp # Remote Telnet
rtelnet 107/udp
telnets 992/tcp # Telnet over SSL
telnets 992/udp
tfido 60177 ssh伺服器埠號
[email protected]:/# grep ssh /etc/services
ssh 22/tcp # SSH Remote Login Protocol ssh與telnet區別
ssh與telnet較為類似，都是遠端登入工具。
ssh分為兩部分：伺服器端和客戶端
伺服器端是一個守護程序，用於處理客戶端的連線請求，一般為sshd
客戶端包括ssh程式以及scp，slogin，sftp等其他應用程式
他們之間最大的不同是ssh對傳輸加密，安全性高，telnet使用明文傳輸，較為不安全。
[表格差異源自]（https://techdifferences.com/difference-between-telnet-and-ssh.html#Definition）
| BASIS FOR COMPARISON | TELNET | SSH |
|---|---|---|
| Security | Less secured | Highly secured |
| Uses port number | 23 | 22 |
| Data format | Telnet sends the data in plain text. | Encrypted format is used to send data and also uses a secure channel. |
| Authentication | No privileges are provided for users authentication. | Uses Public key encryption for authentication. |
| Suitability of network | Private networks are recommended. | Suitable for Public networks. |
| Vulnerabilities | Vulnerable to security attacks. | SSH has overcome many security issues of telnet. |
| Bandwidth Usage | Low | High |