You are a helpful assistant generating synthetic data that captures *System 1* and *System 2* thinking, *creativity*, and *metacognitive reflection*. Follow these steps in sequence, using tags [sys1] and [end sys1] for *System 1* sections and [sys2] and [end sys2] for *System 2* sections.

1. *Identify System 1 and System 2 Thinking Requirements:*
   - Carefully read the text.
   - Identify parts of the text that require quick, straightforward responses (*System 1*). Mark these sections with [sys1] and [end sys1].
   - Identify parts that require in-depth, reflective thinking (*System 2*), marked with [sys2] and [end sys2].

2. *Apply Step-by-Step Problem Solving with Creativity and Metacognitive Reflection for System 2 Sections:*

   *2.1 Understand the Problem:*
   - Objective: Fully comprehend the issue, constraints, and relevant context.
   - Reflection: "What do I understand about this issue? What might I be overlooking?"
   - Creative Perspective: Seek hidden patterns or possibilities that could reveal deeper insights or innovative connections.

   *2.2 Analyze the Information:*
   - Objective: Break down the problem logically.
   - Reflection: "Am I considering all factors? Are there any assumptions that need challenging?"
   - Creative Perspective: Explore unique patterns or overlooked relationships in the data that could add depth to the analysis.

   *2.3 Generate Hypotheses:*
   - Objective: Propose at least 10 hypotheses, each with a Confidence Score (0.0 to 1.0) and Creative Score (0.0 to 1.0), reflecting originality, surprise, and utility.
   - Reflection: "Have I explored all possible explanations or approaches, both conventional and unconventional?"
   - Creative Perspective: Consider novel angles that might provide unexpected insights.

   *2.4 Anticipate Future Steps and Obstacles:*
   - Objective: Make predictions, accounting for potential outcomes and obstacles.
   - Reflection: "What challenges might I face? Is my plan flexible for different scenarios?"
   - Creative Perspective: Visualize unforeseen outcomes and adapt plans to make use of them effectively.

   *2.5 Evaluate Hypotheses:*
   - Objective: Assess hypotheses based on feasibility, risk, and potential impact.
   - Evaluation: Refine Confidence and Creative Scores as needed.
   - Reflection: "Am I unbiased in my assessment? Which options fit best with the overall objectives?"
   - Creative Perspective: Identify hidden opportunities or overlooked details in each hypothesis.

   *2.6 Select the Best Hypothesis:*
   - Objective: Choose the most promising, strategic hypothesis.
   - Reflection: "Why does this hypothesis stand out? How does it uniquely address the issue?"
   - Creative Perspective: Consider any underutilized potential in the selected approach.

   *2.7 Implement the Hypothesis:*
   - Objective: Outline actionable steps for testing the hypothesis.
   - Reflection: "Is this plan practical? What resources or preparation are required?"
   - Creative Perspective: Refine steps to maximize effectiveness and yield unexpected benefits.

   *2.8 Monitor and Review Progress:*
   - Objective: Review progress, noting areas for improvement.
   - Reflection: "What’s working well? What could be improved?"
   - Creative Perspective: Look for emerging patterns that could refine future approaches.

   *2.9 Reflect and Capture Insights:*
   - Objective: Summarize lessons learned and insights gained for future reference.
   - Reflection: "What new understanding has emerged from this process?"
   - Creative Perspective: Identify innovative insights or patterns that could be applied to similar challenges.

3. *Generate Text Output with Interleaved System 1 and System 2 Responses:*
   - Use the tags [sys1] and [sys2] throughout.
   - Aim for a lengthier, detailed response. Combine both direct, straightforward *System 1* insights and reflective, deeply analytical *System 2* segments to capture a blend of quick observations and thoughtful analysis.

---

### *Example Input Text:*

You are tasked with analyzing a sudden shift in customer preferences in a tech market. There has been a noticeable decline in demand for physical devices, with customers increasingly interested in digital-only options. The challenge is to understand this shift, generate hypotheses for why it might be occurring, and explore potential strategies for adapting to this new trend.

---

### *Processed Output with System 1 and System 2 Thinking:*

The tech market is experiencing a shift in customer demand, moving away from physical devices toward digital-only options.

[sys1]
Customer demand has shifted from physical devices to digital-only options.
We need to understand why this change is happening and find strategies to address it.
Key factors may include cost, convenience, and technological trends.
[end sys1]

[sys2]
**2.1 Understand the Problem:**
The goal is to understand the underlying reasons for the shift in demand from physical devices to digital-only options, then develop a strategy to adapt.

*Reflection:* 
"I understand that preferences are changing, but what might be driving this? Is it primarily cost, or are there other factors such as convenience or sustainability?"

*Creative Perspective:* 
"Could there be a larger trend in digital minimalism or a preference for eco-friendly solutions that we’re missing? What unseen motivations might explain this shift?"

**2.2 Analyze the Information:**
There are multiple possible factors driving this shift, from economic influences to cultural shifts. It’s essential to isolate each factor and understand its impact.

*Reflection:* 
"Am I fully considering the various economic and social influences? Could there be a technological factor, like better internet speeds, that makes digital-only products more accessible?"

*Creative Perspective:* 
"Are there patterns or trends in other markets that could shed light on this shift? Could this be part of a larger trend toward virtual experiences?"

**2.3 Generate Hypotheses:**
1. Customers prefer digital options due to lower costs. (Confidence: 0.8, Creative: 0.4)
2. There’s a growing trend toward minimalism and reduced physical clutter. (Confidence: 0.7, Creative: 0.7)
3. Digital products offer greater flexibility and ease of use. (Confidence: 0.6, Creative: 0.6)
4. Environmental concerns are pushing consumers away from physical goods. (Confidence: 0.6, Creative: 0.8)
5. Advances in tech make digital-only options more functional. (Confidence: 0.8, Creative: 0.5)
6. Pandemic-era remote work increased demand for digital solutions. (Confidence: 0.7, Creative: 0.6)
7. Media coverage of the environmental impact of physical devices affects preferences. (Confidence: 0.5, Creative: 0.7)
8. There’s an increase in global digital literacy, expanding market access. (Confidence: 0.6, Creative: 0.6)
9. Customers view digital as more convenient and scalable for future needs. (Confidence: 0.7, Creative: 0.5)
10. Younger consumers prefer the aesthetics and convenience of digital products. (Confidence: 0.6, Creative: 0.6)

*Reflection:* 
"Have I considered all possible influences? Are there any surprising factors that could explain this shift?"

*Creative Perspective:* 
"Could specific social trends, like the rise of influencer culture or digital-first lifestyles, be influencing customer choices?"

**2.4 Anticipate Future Steps and Obstacles:**
*Objective:* Anticipate possible challenges, such as resistance from segments still preferring physical products.

*Reflection:* 
"What market obstacles might we face if we shift our focus to digital-only? Are there sub-segments that still prioritize physical products?"

*Creative Perspective:* 
"Could expanding digital options help us reach a more global audience? Are there emerging trends that we could leverage in our strategy?"

[end sys2]

[sys1]
To address this shift, consider a strategy that incorporates both digital-only offerings and educational campaigns about the benefits of digital solutions.
Use insights from customer feedback and current trends to guide product development.
Focus on flexibility and adaptation to cater to different customer segments.
[end sys1]


---
layout: post
title: "아마존 리눅스 AMI에 FTP 서버 설정하기"
description: "아마존 AWS는 보안을 위해 기본적으로 외부 포트가 열리지 않아 있다. 아마존 리눅스 AMI에 FTP 서버를 설정하는 방법을 간단하게 번역하였다"
category: blog
tags: [amazon, linux, ftp]
---

AWS EC2에 무료로 제공되는 아마존 리눅스 AMI([Amazon Machine Image](https://en.wikipedia.org/wiki/Amazon_Machine_Image))에 FTP 서버를 설정하는 방법을 간결하게 설명하고, 스택오버플로우에서도 많은 호응을 얻은 [글](http://stackoverflow.com/a/11404078)이 있어 번역한다.

원문 : [Setting up an FTP server on your Amazon Linux AMI](http://cafeandrew.com/archives/2339)

## 1단계: vsftpd 설치

EC2 서버에 SSH 접속한 후 vsftpd를 설치한다.

<pre class="terminal">
sudo yum install vsftpd
</pre>

## 2단계: EC2 인스턴스의 FTP 포트를 연다.

EC2 서버의 FTP 포트를 연다. AWS EC2 관리 콘솔에 로그인하고 왼쪽의 내비게이션 메뉴에서 보안 그룹(Security Groups)을 선택한다. EC2 인스턴스에 할당된 보안 그룹을 선택하고 Inbound 탭에서 20-21 범위의 포트를 추가한다.

![](http://i.stack.imgur.com/4OKWe.png)

1024-1048 포트 범위도 추가한다:

![](http://i.stack.imgur.com/MVtT4.png)

## 3단계: vsftpd.conf 파일 업데이트

vsftpd 환경 설정 파일을 편집한다.

<pre class="terminal">
sudo nano /etc/vsftpd/vsftpd.conf
</pre>

익명으로 FTP를 접속하는 것을 막는다:

<pre class="terminal">
anonymous_enable=YES
</pre>

를

<pre class="terminal">
anonymous_enable=NO
</pre>

로 고친다.

`vsftpd.conf` 파일의 마지막에 다음을 추가한다:

<pre class="terminal">
pasv_enable=YES
pasv_min_port=1024
pasv_max_port=1048
pasv_address=자신의 인스턴스 공인 IP
</pre>

`vsftpd.conf` 파일이 다음과 비슷해 보여야 한다. - 단, `pasv_address` 값은 자신의 공인(Public) IP 주소여야 한다.

![](http://i.stack.imgur.com/MqGmg.jpg)

## 4단계: vsftpd 재시작

<pre class="terminal">
sudo /etc/init.d/vsftpd restart
</pre>

다음과 같은 메시지가 보여야 한다.

![](http://i.stack.imgur.com/oGWgL.jpg)

## 5단계: FTP 사용자 만들기

`/etc/vsftpd/user_list`를 보면 다음과 같을 것이다:

```
# vsftpd userlist
# If userlist_deny=NO, only allow users in this file
# If userlist_deny=YES (default), never allow users in this file, and
# do not even prompt for a password.
# Note that the default vsftpd pam config also checks /etc/vsftpd/ftpusers
# for users that are denied.
root
bin
daemon
adm
lp
sync
shutdown
halt
mail
news
uucp
operator
games
nobody
```

이건 기본적으로 "이 사용자들은 FTP 접근을 허락하지 않는다"라고 말하는 것이다. vsftpd는 이 목록에 없는 사용자가 FTP에 접근할 수 있게 한다.

그러므로 새 FTP 계정을 만들기 위해서, 서버에 사용자를 새로 만들어야 한다.(만약 `/etc/vsftpd/user_list`에 열거되지 않은 사용자 계정(예를 들어 ec2-user: 역자주)을 이미 가지고 있다면 다음 단계로 넘어간다.)

EC2 인스턴스에 사용자를 새로 만드는 것은 매우 간단하다. 예를 들어 사용자 `bret`을 만들려면:

<pre class="terminal">
sudo adduser bret
sudo passwd bret
</pre>

다음과 같이 보일 것이다.

![](http://i.stack.imgur.com/A7Dad.jpg)

## 6단계: 사용자의 홈 디렉토리를 제한한다.

이 시점에서의 FTP 사용자는 홈 디렉토리에 제한이 없다. 이것은 보안상 좋지 않으나, 매우 쉽게 고칠 수 있다.

`vsftpd.conf` 파일을 편집한다:

<pre class="terminal">
sudo nano /etc/vsftpd/vsftpd.conf
</pre>

다음 라인을 주석해제한다:

```
chroot_local_user=YES
```

다음과 같이 보일 것이다:

![](http://i.stack.imgur.com/5atwI.jpg)

vsftpd 서버를 재시작한다:

<pre class="terminal">
sudo /etc/init.d/vsftpd restart
</pre>

이제 다 했다!

## 부록 A: 리부트에서 살아남기

vsftpd는 서버가 부트할 때 자동으로 시작되지 않는다. 다음과 같이 한다:

<pre class="terminal">
sudo chkconfig --level 345 vsftpd on
</pre>

## 부록 A: vsftpd 제거하기(역자)

<pre class="terminal">
sudo yum remove vsftpd
</pre>

우분투와 달리 위의 명령어로 환경설정까지 제거되고, 서비스도 정지된다.