(Heavily stolen from and André Bacard's remailer FAQ)

Bálint KOZMAN, 2002.10.26. Budapest

In short: an anonymizer is a tool/service behind which one can "hide" when using some services of the Internet.
Basicly there are two types of anonymizers:

    Anonymizers make web surfing anonymous. The first anonymizer was, developed in 1997 by Lance Cottrell during studies towards a Ph.D. in Astrophysics at the University of California, San Diego. Cottrell is a noted privacy advocate, developed the widely used Mixmaster remailer, and established the Kosovo Privacy Project enabling individuals to anonymously report from within the 1999 Kosovo war zone without fear of retaliation.
    Anonymizers retransmit Internet content similarly to the well-known web-caching proxies. An anonymizer removes all of your identifying information while it surfs for you, enabling you to remain one step removed from the sites you access.
    You can see some of the data that web sites can track about you at the following addresses:, and here is the result about my connection produced by the site. Here you can find a technical description about how these datas were retrieved.
    Most anonymization sites create a URL by appending the name of the site you wish to access to their URL, as in the following example: Once you anonymize an access with an anonymizer prefix, every subsequent link you select is also automatically accessed indirectly and anonymously. Most anonymizers can anonymize at least the web (http:), file transfer protocol (ftp:), and gopher (gopher:) Internet services.
    Anonymization will add up of course some delay in accessing the destination site, depending on your Internet service and time of day. Some anonymizers keep a local cache of several hundred megabytes of commonly accessed sites, so that you can sometimes get a faster access to a site through the anonymizer than through direct access.
    Chaining of anonymization links is not recommended, since it simply multiplies your risk to confidentiality by the number of nodes in the chain. Note that most anonymizers only mask your identity from the destination sites - your surfing can still be intercepted on the way from your computer to the intermediate anonymizer site, for example by your internet service provider. Some anonymizers provide an extra service that encrypts your communications to the anonymizer site as well, rendering your surfing completely confidential.

How to use web-anonymizers?

    Summary: you can anonymize sites one by one, or specify an anonymizer as your start page or proxy server.
To visit a page anonymously, visit your preferred anonymizer site, and then enter the site you want to visit in the
anonymization field. If you set your web browser starting page to an anonymizer, then you can be sure that every subsequent web access you make will be anonymized.
    You can anonymize bookmarks, by prefixing their URL's with the anonymization site address. You can visit an anonymized page, and add it to your bookmarks just like any other page. You can anonymously provide password and other information to sites that request it, if you choose, without revealing any other information such as your IP address. You can configure an anonymizer as your permanent proxy server by making the site name the setting for the HTTP, FTP, Gopher, and other proxy options in your applications configuration menu. Here you can find a small description about how to set up your browser to use an anonymizer.
    Note that proxy servers set up in corporate and institutional networks are usually focused on recording of access logs, and protection from viruses and malicious code, and may not provide identity confidentiality.

Disadvantages/limitations of web-anonymizers Here is a list of sites that provide anonymizer services.


    Summary: Remailers let you send and receive email while keeping your real email address secret.

    Remailers are sites that retransmit your email with an anonymous return address. While encryption provides protection from reading your communications, remailing also protects knowledge of your email's destination. The first widely used remailer was hosted by Johan Helsingius's in Helsinki, Finland. He eventually closed it down when a court case brought by the Church of Scientology forced him to reveal the real email address of a user that had posted information about the Church.
The two most currently popular type of remailers are described below: Most remailers also vary the retention time before remailing to help protect against time-based analyses.

What is a remailer?

    A remailer is a computer service which privatizes your email. High-quality remailers are in sharp contrast to the average Internet Service Provider [ISP] which is terribly anti-private. In many cases, ISP could accurately stand for "Internet Surveillance Project". Almost every ISP can monitor, store, and share your web wanderings and email with many "authorized persons" without your knowledge. In many countries ISPs are monitored constantly by government agencies.

The way a remailer works

    Let's take an elementary, imaginary example. Suppose that a battered woman, Susan, wants to post a message crying out for help. How can Susan post her message and receive responses confidentially? She might use a "PSEUDO anonymous" remailer run by e.g. André Bacard called the "" remailer. (This remailer is fictitious!) If she wrote to him, his "" computer would STRIP AWAY Susan's real name and address (the header at the top of Susan's email), replace this data with a dummy address (for example, <> and forward Susan's message to the newsgroup or person of Susan's choice. Also, his computer would automatically notify Susan that her message had been forwarded under her new identity <>. Suppose that Debbie responds to Susan. André's computer will STRIP AWAY Debbie's real name and address, give Debbie a new identity, and forward the message to Susan. This process protects everyone's privacy. This process is tedious for a person but easy for a computer.

Are there many remailers?

    Yes, there are dozens of popular remailers. Historically, remailers have tended to come and go. First, they require equipment and labor to set up and maintain. Second, a minority of individuals who use remailers are a pain in the neck. These selfish persons drive remailer operators into early retirement. Third, many remailer owners get sick of losing money. I hope we are entering an era of financially profitable remailers. This profitability will permit better reliability and stability.

The difference between a "PSEUDO anonymous" and an "anonymous" remailer

    Most people use the expression "anonymous remailer" as short hand for both types of remailers. This causes confusion. A "PSEUDO anonymous" remailer is basically an account that you open with a remailer operator. The fictitious (described above) is a Pseudo anonymous remailer. This means that I, the operator, and my assistants KNOW your real email address. Your privacy is as good as the remailer operator's power and integrity to protect your records. In practice, what does this mean? Someone might get a court order to force a PSEUDO anonymous remailer operator to reveal your true identity. The Finnish police forced Julf Helsingius to reveal at least one person's true identity. The advantage of most Pseudo anonymous remailers is that they are user-friendly. If you can send email, you can probably understand PSEUDO anonymous remailers. The price you pay for ease of use is less security.
    Truly ANONYMOUS remailers are a different animal. They provide much more privacy than PSEUDO anonymous remailers. However, in general, they are much harder to use than their PSEUDO anonymous cousins.
    There are basically two types of ANONYMOUS remailers. They are called "Cypherpunk remailers" and Lance Cottrell's "Mixmaster remailers". Note that I refer to remailers in the plural. If you want maximum privacy, you should send your message through two or more remailers. If done properly, you can insure that NOBODY (no remailer operator or any snoop) can read both your real name and your message. This is the real meaning of ANONYMOUS. In practice, nobody can force an ANONYMOUS remailer operator to reveal your identity, because the operator has NO CLUE who you are!

New trends in remailers

    A few years ago, Microsoft (with its, Yahoo!, and many other companies began offering free-of-charge, web-based email accounts. You could call these "remailers" (in the broad sense of the word). These email accounts can provide a measure of privacy, if you sign up for them using an alias ("nom d'Internet"), pick good passcodes, and access your account(s) carefully. These (non-encrypted) services are designed for convenience, not privacy or security. Hackers made worldwide headlines when they broke into one of these systems and stole user's passwords.

How safe are remailers?

    For most low-security tasks, such as responding to personal ads, PSEUDO anonymous remailers with passcode protection are undoubtedly safer than using real email addresses. However, all the best made plans of mice and men have weaknesses. Suppose, for example, that you are a government employee, who just discovered that your boss is taking bribes. Is it safe to use a PSEUDO anonymous remailer to send evidence to a government whistle-blower's email hot line? Here are a few points to ponder: