如果您在公司网络中工作过，您可能遇到过代理服务器一词(term proxy server)，并且您知道没有代理服务器您将无法访问公司网络之外的网站和服务。但是，这些代理服务器到底是什么？你应该在家里使用一个吗？阅读本指南以了解为什么需要代理服务器以及何时应该使用代理：
注意(NOTE)：有许多类型的代理服务器可以做各种事情。在本文中，我们指的是最常见的类型 - 有助于访问 Internet 上的内容和服务(content and services)的网络代理。
什么是代理？代理服务器是什么意思？
代理服务器是您的PC 或设备(PC or device)与 Internet之间的中介。该服务器为您向互联网上的网站、服务器和服务发出请求。与代理服务器相关且有时与代理服务器一起使用的概念是VPN（虚拟专用网络(Virtual Private Network)）。阅读何时使用代理以及何时使用VPN？了解差异。
假设你在工作。您正在使用网络浏览器(web browser)访问 www.digitalcitizen.life 并且您的浏览器设置为使用代理服务器(proxy server)。键入 www.digitalcitizen.life 后，请求将发送到代理服务器(proxy server)。然后代理服务器(proxy server)将请求发送到托管我们网站的服务器。我们网站的主页返回给代理服务器(proxy server)，代理服务器又将其返回给您。因此，我们的网站将代理服务器(proxy server)视为实际访问者，而不是您的计算机。下图说明了这种信息交换，并搜索了一个简单问题的答案：当前时间是几点？
现在您已经了解了基础知识，让我们看看使用代理服务器获得的好处。
代理服务器是做什么用的？
代理服务器(proxy server)的概念提供了惊人的大量优势：
- 控制(Control internet)企业网络中的互联网使用
- 大型网络的带宽(Bandwidth)节省
- 提高速度
- 隐私
- 安全
- 绕过审查
让我们一一了解这些好处，并阐明它们如何为您服务。
使用代理服务器控制互联网(Control internet)使用
代理在企业网络中广泛使用的最重要原因之一是它们可以控制员工在互联网上访问和使用的内容。例如，许多公司禁止某些网站，以便员工在工作时间无法访问它们。例如，他们可能会禁止成人网站、流行的社交网络或像 9gag.com 这样浪费时间的网站。
强制员工仅通过您公司的代理访问互联网也意味着您拥有他们访问的所有网站和内容的详细日志、访问时间和访问时间。每个员工都有详细的使用报告，公司可以快速识别行为不端的用户。
(Bandwidth)使用代理服务器时节省(proxy server)带宽并提高速度
公司使用代理服务器的另一个原因是它可以帮助他们节省宝贵的带宽。代理服务器可以压缩来自 Internet 的流量、缓存文件和网页，甚至可以在网站的广告到达您的计算机之前将其从网站上剥离。它允许公司节省带宽，特别是当他们有成百上千的员工访问大多数相同的流行网站（例如，CNN、纽约时报(New York Times)、维基百科(Wikipedia)等）时。
当一个网页(web page)被访问时，代理服务器可以存储它，当下一个人请求它时，它首先检查页面是否发生了变化。如果它没有改变，它会转发本地副本而不重新下载整个页面。这既为公司节省了带宽，又使下一个请求相同资源的人的加载过程更快。
隐私优势：隐藏您的IP 地址(IP address)、位置和其他信息
当您直接连接到互联网并加载网站时，托管它的服务器可以看到您的IP 地址(IP address)。借助此地址，它可以大致估算您的地理位置。此外，浏览器发送其用户代理信息(agent information)，网站知道您使用的是什么浏览器。最重要的是，cookie 存储在您的计算机上，它们提供更多的个人信息。
代理服务器可以隐藏您的IP 地址(IP address)（如果它们被设置为这样做），可以发送不同的用户代理(user agent)，这样您的浏览器就不会被识别，并且可以阻止 cookie 或接受它们，但不能将它们传递到您的PC 或设备(PC or device)。因此，使用代理服务器(proxy server)时，您可以比使用直接连接到 Internet 时更加匿名。
代理服务器可以提高安全性
代理(Proxy)服务器也可能在提高安全性方面发挥作用，尤其是在用于商业网络时。它们可以设置为阻止对分发恶意软件(distribute malware)的恶意网站的访问，它们还可以提供加密服务，这样您的数据就不会被想要获取数据的第三方轻易嗅探。
代理(Proxy)服务器可以提供对网络上被阻止资源的访问
代理服务器的一个流行用途是绕过互联网审查。例如，中国或伊朗(China or Iran censor access)等国家对互联网上许多网站和服务的访问进行审查。这些国家的用户可以使用代理服务器来规避这种审查并访问它们。
此外，有些服务仅在特定国家/地区可用。例如，Hulu仅适用于美国和日本(US and Japan)的用户。欧洲人(Europe)可以使用位于美国的代理服务器(proxy server)来访问它。
我应该使用代理服务器(proxy server)吗？代理服务器(proxy server)可能产生的安全问题。
使用代理服务器并不全是好处和好东西。他们可能会带来以下问题：
- 当使用未加密的连接时，代理服务器可以改变您收到的响应，无论是好的还是坏的。例如，受感染或恶意代理服务器可用于将恶意软件加载到您的浏览器或将您重定向到网络钓鱼网站(phishing website)。
- 代理可以更改您对 Internet 上的网站或服务(website or service)提出的请求，以生成符合他人意图的结果。
- 代理服务器监视并记录您的活动。因此，它存储了大量关于您的信息，可用于日后的身份识别。
- 根据其配置方式，代理服务器可以提供未加密的数据，其中加密数据之前由您使用的网站或服务提供。(website or service)它可以让您暴露在网络嗅探之下，并让其他人监控您在互联网上所做的事情。
如何在您的计算机和设备上使用代理服务器
在所有主要操作系统中配置代理服务器(proxy server)的使用很容易： Windows、Android、iOS 等。如果您决定设置代理服务器(proxy server)，请参阅我们的教程以获得帮助：
- 如何在Windows 10中设置(Windows 10)代理服务器(proxy server)设置
- 如何在Chrome、Firefox、Internet Explorer、Microsoft Edge和Opera中设置代理服务器(Opera)
- 如何在Android上为(Android)WiFi设置代理服务器的使用(WiFi)
- 如何在 iPhone 或 iPad 上为Wi-Fi设置代理服务器的使用(Wi-Fi)
- 如何在Windows 8.1平板电脑或混合设备上设置代理服务器
您寻找代理服务器解决方案(server solution)的原因是什么？
如您所见，代理服务器(proxy server)可能很棒，但它们也可能是一个问题。这完全取决于它们的配置方式、保护方式以及由谁管理。代理服务器(proxy server)可能提供上述所有好处，也可能不提供。这一切都取决于它是如何设置的以及为什么。在使用代理服务器(proxy server)之前，重要的是要了解您使用它的原因、谁控制代理服务器(proxy server)以及它是否由受信任的一方管理。警惕公共代理服务器(proxy server)你几乎一无所知。一些公共代理可用于恶意目的，它们会使您面临问题而不是提供好处。如果您对值得分享的代理有任何疑问或经验，请随时在下面发表评论。
Simple Questions: What is a proxy server and what does it mean?
If you have worked in a corporate network, you hаve probаbly encountered the tеrm proxу server, and you know that withоut one yoυ cannot access websitеs and services outside the compаny's network. However, what exactly are these proxy servers? Should you use onе at home? Read this guide tо leаrn why proxy sеrvers are necessary and when you should use a proxy:
NOTE: There are many types of proxy servers that do all kinds of things. In this article, we refer to the most common type - web proxies that facilitate access to the content and services found on the internet.
What is a proxy? What does proxy server mean?
A proxy server is an intermediary between your PC or device and the internet. This server makes requests to websites, servers and services on the internet for you. A concept related and sometimes used together with a proxy server is VPN (Virtual Private Network). Read When to use a proxy and when to use a VPN? to understand the difference.
Let's assume that you are at work. You are using a web browser to visit www.digitalcitizen.life and your browser is set to use a proxy server. After you type www.digitalcitizen.life, the request is sent to the proxy server. The proxy server then sends the request to the server where our website is hosted. The homepage of our website is returned to the proxy server which, in turn, returns it to you. As a result, our website sees the proxy server as the actual visitor, rather than seeing your computer. This exchange of information is illustrated in the image below with the search for an answer to a simple question: what is the current time?
Now that you know the basics, let's see the benefits you get by using a proxy server.
What is a proxy server used for?
The concept of the proxy server offers a surprisingly large number of advantages:
- Control internet usage in corporate networks
- Bandwidth savings for large networks
- Improved speed
- Privacy
- Security
- Bypass censorship
Let's take these benefits one by one and clarify how they can work for you.
Control internet usage using proxy servers
One of the most important reasons why proxies are widely used in corporate networks is that they provide control over what employees are accessing and using on the internet. For example, many companies ban certain websites so that employees do not access them during work hours. For example, they may ban adult websites, popular social networks or time-wasting websites like 9gag.com.
Forcing employees to access the internet only through your company's proxy also means that you have detailed logs of all the websites and content that they accessed, when, and for how long. Detailed usage reports are available about each employee, and the company can quickly identify misbehaving users.
Bandwidth savings and improved speed when using a proxy server
Another reason why companies use proxy servers is that it helps them save precious bandwidth. Proxy servers can compress traffic, cache files and web pages from the internet and even strip ads from websites before they reach your computer. It allows companies to save bandwidth, especially when they have hundreds or thousands of employees, accessing mostly the same popular websites (e.g., CNN, New York Times, Wikipedia, etc).
When a web page is accessed, a proxy server can store it and, when the next person requests it, it first checks if the page has changed. If it has not changed, it forwards the local copy without re-downloading the whole page. This both saves bandwidth for the company and makes the loading process faster for the next person that requests the same resource.
Privacy benefits: hide your IP address, location, and other information
When you have a direct connection to the internet, and you load a website, the server where it is hosted can see your IP address. With the help of this address, it can approximate your geographical location. Also, the browser sends its user agent information, and the website knows what browser you are using. On top of this, cookies are stored on your computer, and they provide further personal information.
Proxy servers can hide your IP address (if they are set to do this), can send a different user agent so that your browser is not identified and can block cookies or accept them but not pass them to your PC or device. Therefore, when using a proxy server, you can be more anonymous than when using a direct connection to the internet.
Proxy servers can improve security
Proxy servers may also have a role in improving security, especially when used in business networks. They can be set to block access to malicious websites that distribute malware, and they can also provide encryption services so that your data is not easily sniffed by third-parties that want to get their hands on it.
Proxy servers may provide access to blocked resources on the web
A popular use for proxy servers is the bypassing of internet censorship. For example, countries like China or Iran censor access to many websites and services on the internet. Users in those countries can use proxy servers to circumvent this censorship and get access to them.
Also, there are services which are available only in specific countries. For example, Hulu works only for users based in the US and Japan. People in Europe can use a proxy server based in the US to access it.
Should I use a proxy server? Possible security problems generated by proxy servers.
Using proxy servers is not all about benefits and good stuff. They can pose problems like:
- When using unencrypted connections, the proxy server can alter the responses you receive, both in good and bad ways. For example, an infected or malicious proxy server can be used to load malware into your browser or redirect you to a phishing website.
- A proxy can alter the requests you make to a website or service on the internet to generate results that meet someone else's intentions.
- A proxy server monitors and logs your activity. Therefore, it stores lots of information about you that can be used for identification at a later date.
- Depending on how it was configured, a proxy server can provide unencrypted data where encrypted data was previously provided by the website or service you are using. It can expose you to network sniffing and having others monitor what you are doing on the internet.
How to use a proxy server on your computers and devices
It is easy to configure the use of a proxy server in all the major operating systems: Windows, Android, iOS, and so on. If you decide to set up a proxy server, see our tutorials for assistance:
What is your reason for looking for a proxy server solution?
As you can see, proxy servers can be great, and they can also be a problem. It all depends on how they are configured, how they are secured and by whom they administered. A proxy server may provide all the benefits mentioned above or none of them. It all depends on how it was set up and why. Before using a proxy server, it is important to understand why you are using it, who controls the proxy server and whether it is administered by a trusted party. Be wary of public proxy servers of which you know next to nothing. Some public proxies can be used for malicious purposes, and they can expose you to problems instead of providing benefits. If you any questions or experiences with proxies that are worth sharing, do not hesitate to leave a comment below.
