9.1.3 Web Mail
A second option for e-mail is to use a web based e-mail account. This will allow you to use a
web browser to check your e-mail. Since the e-mail for these accounts is normally stored on
the web e-mail server – not on your local computer – it is very convenient to use these
services from multiple computers. It is possible that your ISP will allow you to access your e-mail
through both POP and the web.
However, you must remember that web pages are cached or stored on local computers,
sometimes for significant lengths of time. If you check your e-mail through a web based
system on someone else's computer, there is a good chance that your e-mails will be
accessible to someone else who uses that computer.
Web based e-mail accounts are often free and easy to get. This means that they offer an
opportunity for you to have several identities online. You can, for instance, have one e-mail
address that you use only for friends and another that is only for relatives. This is usually
considered acceptable, as long as you are not intentionally intending to defraud anyone.
9.1.3 網頁郵件
第二種電子郵件形式是使用基於網頁的電子郵件賬戶。你可以通過網頁瀏覽器查看電子郵件。因爲郵件一般都是存儲在網頁郵件服務器上---不是本地電腦上---所以這些服務方便不同電腦使用。你的ISP可能會讓你通過POP和網頁兩種方式來收發郵件。
但是，要注意網頁時存儲到本地電腦上的，有的時候會存儲相當長的時間。如果你在別人的電腦上通過網頁瀏覽器收發郵件，你的郵件就很有可能被其他使用該電腦的人發現。
基於網頁的電子郵件賬戶通常是免費的，而且創建起來很方便。就是說你可以創建幾個不同的賬戶。你可以用一個賬號專門和朋友通信，另一個賬號用來給親戚通信。只要你不是有意欺騙別人，那麼這樣做完全是可以的。
Exercises:
1. You can learn a lot about how POP e-mail is retrieved by using the telnet program. When
you use telnet instead of an e-mail client, you have to enter all the commands by hand
(commands that the e-mail client program usually issues automatically). Using a web
search engine, find the instructions and commands necessary to access an e-mail
account using the telnet program. What are the drawbacks to using this method to
retrieve e-mail? What are some of the potential advantages?
2. Find three organizations that offer web based e-mail services. What, if any, promises do
they make about the security of e-mail sent or received using their services? Do they make
any attempts to authenticate their users?
3. (possibly homework) Determine the SMTP server for the email address you use most
frequently.
練習：
1、你可以用telnet程序學習POP是怎麼取回的電子郵件的。當你使用telnet，不用電子郵件客戶端，你就需要自己手動鍵入命令（而電子郵件客戶端是自動調用這些命令的）。用一個搜索引擎查找用遠程程序登陸電子郵件賬戶所需要的指令。使用這種方法取回郵件的缺點是什麼？但又有哪些潛在好處呢？
2、找出3個提供基於網絡電子郵件服務的組織。他們都對電子郵件發送和接收的安全都做出了哪些承諾？他們有沒有驗證用戶的身份？
3、（家庭作業）找出你經常使用的電子郵件地址所使用的SMTP服務器。
9.2 Safe E-mail Usage Part 1: Receiving
Everyone uses e-mail, and to the surprise of many people, your e-mail can be used against
you. E-mail should be treated as a post card, in that anyone who looks can read the
contents. You should never put anything in an ordinary e-mail that you don’t want to be
read. That being said there are strategies for securing your e-mail. In this section we will cover
safe and sane e-mail usage and how to protect your privacy online.
9.2.1 Spam, Phishing and Fraud
Everybody likes to get e-mail. A long time ago, in a galaxy far far away it used to be you only
got mail from people you knew, and it was about things you cared about. Now you get email
from people you never heard of asking you to buy software, drugs, and real estate, not
to mention help them get 24 million dollars out of Nigeria. This type of unsolicited advertising is
called spam. It comes as a surprise to many people that e-mail they receive can provide a
lot of information to a sender, such as when the mail was opened and how many times it was
read, if it was forwarded, etc. This type of technology – called web bugs – is used by both
spammers and legitimate senders. Also, replying to an e-mail or clicking on the unsubscribe
link may tell the sender that they have reached a live address. Another invasion of privacy
concern is the increasingly common “phishing” attack. Have you ever gotten an e-mail
asking you to login and verify your bank or E-bay account information? Beware, because it is
a trick to steal your account information. To secure yourself against these types of attacks,
there are some simple strategies to protect yourself outlined below.
9.2 安全郵件使用 第一部分：接收郵件
幾乎所有的人都使用電子郵件，但很多人不知道的是，當電子郵件使用不當時會對你產生不利的郵箱。電子郵件就和明信片一樣，每個人收到明信片的人都能看懂其中的內容。不要將你不想被別人知道的內容寫到一封普通郵件中。不過還是有些保證電子郵件安全的方法。這部分我們將介紹怎麼安全使用電子郵件，如何保護自己的隱私。
9.2.1 垃圾郵件和詐騙郵件
任何人都想收到一封郵件，很久以前，你只能收到你認識的人的來信，說的內容也是你所關係的。現在你收到一些陌生人發過來的郵件，讓你購買軟件，藥品和房子，更不用說那些更不靠譜的郵件了。這些廣告形式的郵件就是垃圾郵件，很多人不知道的是他們收到的郵件會給發送者提供很多的信息，譬如該郵件什麼時候打開的，被讀過多少次，是不是被轉發過等等。這種技術---叫做網頁漏洞---被髮送垃圾郵件的人和合法的發送者使用。也有可能，回信或者點擊退出都會告訴發送者一個地址。另一種對隱私的侵犯是最常用的釣魚攻擊。有沒有收到一封郵件讓你登陸並更改銀行或者Ebay賬戶信息？注意，這是一種竊取你賬號信息的騙局。爲了避免這些攻擊，下面列出了一些保護自己的簡單方法。