Okay, I need to write professional and informative wiki document SSH under the technology category. Let me start by understanding the structure required. The wants a clear H1, an overview section, several detailed sections using H2 and H3 and possibly a references section The content should be accurate objective, and thorough.
First, the is straightforward: SSH. the overview should introduce what SSH is, its purpose and maybe a bit of history. I should that it's a network for secure data communication, replacing insecure protocols like Telnet Also, note that it developed by Tatu Ylönen in 1995.
Next, the detailed sections. The user mentioned H2 and H3. Let me think about the key aspects of SSH. Common sections would be Core Concepts, Technical Details, Applications, Security Considerations, and maybe Implementation Examples.
For Core Concepts, I can explain the client-server model, authentication methods (password, public key), and encryption techniques. Public key authentication is important here, so I should explain how it works with key pairs. Also, mention the three layers: Transport, Authentication, and Connection.
Technical Details should cover the protocol structure, port usage (default port 22), key exchange methods like Diffie-Hellman. include the encryption algorithms used, such as AES, ChaCha20, and hashing algorithms like SHA-2. Also, discuss how integrity is maintained with message authentication codes.
Applications of SSH are varied. Remote server access is primary. Then there's tunneling, like local and remote port forwarding. SCP and SFTP for file transfers. Also, automation in DevOps with tools like Ansible or Jenkins using SSH keys for secure deployments.
Security Considerations need to address best practices. Strong passwords vs. key-based authentication, disabling root login, using non-standard ports, rate limiting with tools like fail2ban. Also, mention potential vulnerabilities, like MITM attacks if keys aren't properly managed, and the importance of key management practices.
Implementation Examples would be practical commands. Show how to connect to a server with ssh user@hostname. Generating key pairs with ssh-keygen, copying public keys with ssh-copy-id. Configuring the SSH daemon by editing /etc/ssh/sshd_config, changing the port, disabling password login, etc. Maybe an example of port forwarding: ssh -L 8080:localhost:80 user@hostname.
I should also include a section on Related Protocols and Technologies, comparing SSH with TLS/SSL, IPSec, and mentioning OpenSSH as the most common implementation. References to RFC 4251-4256 for the standards.
Need to ensure that technical terms are explained. For example, when talking about encryption algorithms, briefly describe what AES is. Also, make sure the document is at least 800 characters, but the user example seems longer, so expanding each section with enough detail is necessary.
Check for markdown formatting: H1 for the title, H2 for major sections, H3 where needed. Use bullet points for lists, maybe tables for algorithms. Code blocks for commands. Avoid markdown in the thinking process, but in the final answer, apply it correctly.
Wait, in the sample response, they used H2 for sections like "개요", "핵심 개념", "기술적 세부 사항", etc. Then H3 for subsections like "인증 방식" under "핵심 개념". So structure would be:
SSH
개요
역사
핵심 개념
인증 방식
암호화 기술
프로토콜 계층
기술적 세부 사항
프로토콜 구조
포트 및 통신 방식
사용되는 암호화 알고리즘
주요 활용 분야
원격 서버 접속
터널링 (포트 포워딩)
파일 전송 (SCP, SFTP)
자동화 및 DevOps
보안 고려사항
보안 취약점
권장 보안 설정
구현 및 사용 예시
SSH 클라이언트 사용법
키 페어 생성
SSH 서버 설정
관련 프로토콜 및 기술
참고 자료
I need to follow this structure. Make sure each H2 has H3 subsections where appropriate. Use bullet points for lists, code blocks for commands. Also, ensure the content is in Korean, but the thinking is in English.
Wait, the user provided a sample answer in Korean. So the final answer should be in Korean. But my thinking process here is in English. That's correct.
I need to make sure that each section is filled with accurate information. For example, in the history section, SSH was created by Tatu Ylönen in 1995 after a password sniffing attack. Version 1 had vulnerabilities, so version 2 was developed with more secure algorithms.
In authentication methods, password-based is simple but susceptible to brute force. Public key is more secure, using a private and public key. Also, mention key-based authentication steps: generate key pair, copy public key to server, login without password.
Encryption techniques: symmetric algorithms like AES, asymmetric for key exchange, hashing for integrity. The three layers: Transport (encryption), Authentication (user verification), Connection (multiplexing sessions).
Technical details: SSH operates over TCP, port 22. Diffie-Hellman key exchange for secure key sharing. Algorithms like AES, ChaCha20, HMAC for message integrity.
Applications: Remote access, tunneling (local, remote, dynamic port forwarding), SCP/SFTP for secure file transfers, automation using SSH keys in scripts or DevOps tools.
Security considerations: Use public key instead of passwords, disable root login, change default port, limit login attempts, regular updates. Vulnerabilities like MITM if keys aren't managed, weak algorithms (e.g., using SHA-1), and key management (revoking keys when compromised).
Implementation examples: Commands like ssh user@hostname, ssh-keygen, ssh-copy-id. Configuring sshd_config to set PermitRootLogin no, PasswordAuthentication no, etc.
Related protocols: Compare with TLS/SSL (used for web security), IPSec (network layer encryption), OpenSSH as the open-source implementation.
References: RFC 4251-4256, OpenSSH website, NIST guidelines.
I need to ensure all these points are covered in the markdown structure. Also, check that explanations are clear and terms are properly defined. For example, explain what port forwarding is in the tunneling section. Use examples where possible to illustrate points. Avoid overly technical jargon without explanation. Keep paragraphs concise for readability.
Make sure the document meets the length requirement. Each section should have sufficient detail. For instance, in encryption algorithms, list a few examples and their key sizes. In the history, mention the transition from SSH-1 to SSH-2 due to security issues.
Also, check for any inaccuracies. For example, SSH does use TCP, but sometimes UDP in some implementations? No, primarily TCP. Or is that incorrect? Let me confirm: SSH typically uses TCP port 22, as per standard. Some implementations might use UDP for certain purposes, but that's not standard. Probably safe to say TCP.
Another point: SCP vs SFTP. SCP is based on RCP and uses SSH for encryption. SFTP is a separate protocol over SSH, more feature-rich. Should mention that in the file transfer section.
Also, mention that SSH can be used for X11 forwarding, allowing GUI applications to be run remotely. Maybe in the applications or tunneling section.
In the security section, mention that using non-standard ports can reduce automated attacks but isn't a substitute for proper security. Also, key management: protecting private keys with passphrases, storing them securely.
In the implementation examples, show how to set up port forwarding, like local port 8080 to remote host's port 80. Also, using -i option with ssh to specify a private key.
Need to organize all this into the structure. Now, time to put it all together in Korean markdown.