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URL redirection, also called URL forwarding, domain redirection and domain forwarding, is a technique on the World Wide Web for making a web page available under many URLs. WWWs historical logo designed by Robert Cailliau The World Wide Web (commonly shortened to the Web) is a system of interlinked, hypertext documents accessed via the Internet. ...
A screenshot of a web page. ...
// Uniform Resource Locator (URL) formerly known as Universal Resource Locator, is a technical, Web-related term used in two distinct meanings: In popular usage and many technical documents, it is a synonym for Uniform Resource Identifier (URI); Strictly, the idea of a uniform syntax for global identifiers of network-retrievable...
Purposes There are several reasons for a webmaster to use redirection:
Similar domain names A web browser user might mis-type a URL -- for example, "gooogle.com" and "googel.com". Organizations often register these "mis-spelled" domains and re-direct them to the "correct" location: google.com. For example: the addresses example.com and example.net could both redirect to a single domain, or web page, such as example.org. This technique is often used to "reserve" other TLDs with the same name, or make it easier for a true ".edu" or ".net" to redirect to a more recognizable ".com" domain.
Moving a site to a new domain Why redirect a web page? - A web site might need to change its domain name.
- An author might move his or her pages to a new domain.
- Two web sites might merge.
With URL redirects, incoming links to an outdated URL can be sent to the correct location. These links might be from other sites that have not realized that there is a change or from bookmarks/favorites that users have saved in their browsers.
The same applies to search engines. They often have the older/outdated domain names and links in their database and will send search users to these old URLs. By using a "moved permanently" redirect to the new URL, visitors will still end at the correct page. Also, in the next search engine pass, the search engine should detect and use the newer URL. A search engine is an information retrieval system designed to help find information stored on a computer system. ...
Logging outgoing links The access logs of most web servers keep detailed information from where visitors came and how they browsed the hosted site. They do not, however, log which links visitors left by. This is because the visitor's browser has no need to communicate with the original server when the visitor clicks on an out-going link.
This information can be captured in several ways. One way involves URL redirection. Instead of sending the visitor straight to the other site, links on the site can direct to a URL on the original website's domain that automatically redirects to the real target. This added request will leave a trace in the server logs saying exactly which link was followed. This technique is also used by some corporate websites to have a "warning" page that the content is off-site and not necessarily affiliated with the corporation. This technique does bear the downside in the delay of an additional request to the original website's server. For websites that wish to display a "warning" page before automatically forwarding, the length of time the warning is displayed is an additional delay.
Short, meaningful, persistent aliases for long or changing URLs Currently, web engineers tend to pass descriptive attributes in the URL to represent data hierarchies, command structures, transaction paths and session information. This results in a URL that is aesthetically unpleasant and difficult to remember. Sometimes the URL of a page changes even though the content stays the same.
Manipulating search engines Some years ago, redirect techniques were used to fool search engines. For example, one page could show popular search terms to search engines but redirect the visitors to a different target page. There are also cases where redirects have been used to "steal" the page rank of one popular page and use it for a different page, usually involving the 302 HTTP status code of "moved temporarily." [1] [2] The following is a list of HTTP response status codes and standard associated phrases, intended to give a short textual description of the status. ...
Search engine providers noticed the problem and took appropriate actions. Usually, sites that employ such techniques to manipulate search engines are punished automatically by reducing their ranking or by excluding them from the search index.
As a result, today, such manipulations usually result in less rather than more site exposure.
Satire and criticism In the same way that a Google bomb can be used for satire and political criticism, a domain name that conveys one meaning can be redirected to any other web page, sometimes with malicious intent. Example of a Google bomb. ...
Manipulating visitors URL redirection is sometimes used as a part of phishing attacks that confuse visitors about which web site they are visiting. An example of a phishing email, disguised as an official email from a (fictional) bank. ...
Techniques There are several techniques to implement a redirect. In many cases, Refresh meta tag is the simplest one. However, there exist several strong opinions discouraging this method. Meta refresh is an HTML meta element used to specify a time-interval (in seconds) after which a web browser should automatically refresh the current web page. ...
Manual redirect The simplest technique is to ask the visitor to follow a link to the new page, usually using an HTML anchor as such: Please follow <a href="http://www.example.com/">link</a>! This method is often used as a fall-back for automatic methods — if the visitor's browser does not support the automatic redirect method, the visitor can still reach the target document by following the link.
HTTP status codes 3xx In the HTTP computer protocol used by the World Wide Web, a redirect is a response with a status code beginning with 3 that induces a browser to go to another location. HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ...
This article is about the machine. ...
For other senses of this word, see protocol. ...
WWWs historical logo designed by Robert Cailliau The World Wide Web (commonly shortened to the Web) is a system of interlinked, hypertext documents accessed via the Internet. ...
The following is a list of HTTP response status codes and standard associated phrases, intended to give a short textual description of the status. ...
The HTTP standard defines several status codes for redirection:
- 300 multiple choices (e.g. offer different languages)
- 301 moved permanently
- 302 found (e.g. temporary redirect)
- 303 see other (e.g. for results of cgi-scripts)
- 307 temporary redirect
All of these status codes require that the URL of the redirect target is given in the Location: header of the HTTP response. The 300 multiple choices will usually list all choices in the body of the message and show the default choice in the Location: header.
Within the 3xx range, there are also some status codes that are quite different from the above redirects (they are not discussed here with their details):
- 304 not modified
- 305 use proxy
- 306 not used
This is a sample of a HTTP response that uses the 301 "moved permanently" redirect: HTTP/1.1 301 moved permanently Location: http://www.example.org/ Content-type: text/html Content-length: 78 Please follow <a href="http://www.example.org/">link</a>!
Using server-side scripting for Redirection Often, web authors don't have sufficient permissions to produce these status codes: The HTTP header is generated by the web server program and not read from the file for that URL. Even for CGI scripts, the web server usually generates the status code automatically and allows custom headers to be added by the script. To produce HTTP status codes with cgi-scripts, one needs to enable non-parsed-headers.
Sometimes, it is sufficient to print the "Location: 'url'" header line from a normal CGI script. Many web servers choose one of the 3xx status codes for such replies.
The HTTP protocol requires that the redirect be sent all by itself, without any web page data. As a result, the web programmer who is using a scripting language to redirect the user's browser to another page must ensure that the redirect is the first or only part of the response. In the ASP scripting language, this can also be accomplished using the methods response.buffer=true and response.redirect "http://www.example.com". Using PHP, one can use header("Location: http://www.example.com");. Active Server Pages (ASP) is Microsofts first server-side script engine for dynamically-generated web pages. ...
For other uses, see PHP (disambiguation). ...
According to the HTTP standard, the Location header must contain an absolute URI. When redirecting from one page to another within the same site, it is a common mistake to use a relative URI. As a result most browsers tolerate relative URIs in the Location header, but some browsers display a warning to the end user. A Uniform Resource Identifier (URI), is a compact string of characters used to identify or name a resource. ...
Using .htaccess for Redirection When using the Apache web server, directory-specific .htaccess files (as well as apache's main configuration files) can be used. For example, to redirect a single page: The Apache HTTP Server, commonly referred to simply as Apache, is a web server notable for playing a key role in the initial growth of the World Wide Web. ...
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Redirect 301 /oldpage.html http://www.example.com/newpage.html To change domain names: RewriteEngine On RewriteCond %{HTTP_HOST} ^.*oldwebsite.com$ [NC] RewriteRule ^(.*)$ http://www.preferredwebsite.net/$1 [R=301,L] Use of .htaccess for this purpose usually does not require administrative permissions, though it can be disabled.
Refresh Meta tag and HTTP refresh header Netscape introduced a feature to refresh the displayed page after a certain amount of time. This method is often called meta refresh. It is possible to specify the URL of the new page, thus replacing one page after some time by another page: For the web browser produced by this corporation, see Netscape (web browser). ...
Meta refresh is an HTML meta element used to specify a time-interval (in seconds) after which a web browser should automatically refresh the current web page. ...
A timeout of 0 seconds means an immediate redirect.
This is an example of a simple HTML document that uses this technique:
<html><head> <meta http-equiv="Refresh" content="0; url=http://www.example.com/"> </head><body> <p>Please follow <a href="http://www.example.com/">link</a>!</p> </body></html> - This technique is usable by all web authors because the meta tag is contained inside the document itself.
- The meta tag must be placed in the "head" section of the HTML file.
- Note the strange syntax of the content field.
- The number "0" in this example may be replaced by another number to achieve a delay of as many seconds.
- Many users regard a delay of this kind as annoying unless there is a reason for it.
- This is a proprietary/non-standard extension by Netscape. It is supported by most web browsers.
This is an example of achieving the same effect by issuing a HTTP refresh header: HTTP/1.1 200 ok Refresh: 0; url=http://www.example.com/ Content-type: text/html Content-length: 78 Please follow <a href="http://www.example.com/">link</a>! This response is easier to generate by CGI programs because one does not need to change the default status code. Here is a simple CGI program that effects this redirect: #!/usr/bin/perl print "Refresh: 0; url=http://www.example.com/rn"; print "Content-type: text/htmlrn"; print "rn"; print "Please follow <a href="http://www.example.com/">link</a>!" Note: Usually, the HTTP server adds the status line and the Content-length header automatically.
This method is considered by the W3C to be a poor method of redirection, since it does not communicate any information about either the original or new resource, to the browser (or search engine). The W3C's Web Content Accessibility Guidelines (7.4) discourage the creation of auto-refreshing pages, since most web browsers do not allow the user to disable or control the refresh rate. Some articles that they have written on the issue include W3C Web Content Accessibility Guidelines (1.0): Ensure user control of time-sensitive content changes and Use standard redirects: don't break the back button! WWWC redirects here. ...
A search engine is an information retrieval system designed to help find information stored on a computer system. ...
JavaScript redirects JavaScript offers several ways to display a different page in the current browser window. Quite frequently, they are used for a redirect. However, there are several reasons to prefer HTTP header or the refresh meta tag (whenever it is possible) over JavaScript redirects: JavaScript is a scripting language most often used for client-side web development. ...
- There are several reasons for some users to disable JavaScript:
- Security considerations
- Some browsers don't support JavaScript
- many crawlers (e.g. from search engines) don't execute JavaScript.
- There is no "standard" way of doing it: A search for "you are being redirected" will find that virtually each JavaScript redirect employs different methods. This makes it difficult for Web client programmers to honor your redirect request without implementing all of JavaScript.
Frame redirects A slightly different effect can be achieved by creating a single HTML frame that contains the target page: In computing, an HTML element indicates structure in an HTML document and a way of hierarchically arranging content. ...
<frameset rows="100%"> <frame src="http://www.example.com/"> </frameset> <noframes> Please follow <a href="http://www.example.com/">link</a>! </noframes> One main difference to the above redirect methods is that for a frame redirect, the browser displays the URL of the frame document and not the URL of the target page in the URL bar.
This technique is commonly called cloaking. This may be used so that the reader sees a more memorable URL or, with fraudulent intentions, to conceal a phishing site as part of website spoofing.[3] An example of a phishing email, disguised as an official email from a (fictional) bank. ...
Website spoofing is the act of creating a website, as a hoax, with the intention of misleading readers that the website has been created by a different person or organisation. ...
Redirect loops It is quite possible that one redirect leads to another redirect. For example, the URL http://www.wikipedia.com/wiki/URL_redirection (note the differences in the domain name) is first redirected to http://www.wikipedia.org/wiki/URL_redirection and again redirected to the correct URL: http://en.wikipedia.org/wiki/URL_redirection. This is appropriate: the first redirection corrects the wrong domain name. The second redirection selects the correct language section. Finally, the browser displays the correct page.
Sometimes, however, a mistake can cause the redirection to point back to the first page, leading to an infinite loop of redirects. Browsers usually break that loop after a few steps and display an error message instead.
The HTTP standard states:
- A client SHOULD detect infinite redirection loops, since such loops generate network traffic for each redirection.
Previous versions of this specification recommended a maximum of five redirections; some clients may exist that implement such a fixed limitation.
Services There exist services that can perform URL redirection on demand, with no need for technical work or access to the webserver your site is hosted on. Image File history File links Mergefrom. ...
URL redirection services URL redirection services exist to shorten long URLs. // Uniform Resource Locator (URL) formerly known as Universal Resource Locator, is a technical, Web-related term used in two distinct meanings: In popular usage and many technical documents, it is a synonym for Uniform Resource Identifier (URI); Strictly, the idea of a uniform syntax for global identifiers of network-retrievable...
Some web publishers have criticized the use of these services, arguing that replacing a URL with an encoded shortcut effectively erases information from a document. For instance, a redirected URL may link to a blacklisted site.
Hyperlinks involving URL redirection services are frequently used in spam messages directed at blogs and wikis. Thus, one way to reduce spam is to reject all edits and comments containing hyperlinks to known URL redirection services; however, this will also remove legitimate edits and comments and may not be an effective method to reduce spam.
Recently, URL redirection services have taken to using AJAX as an efficient, user friendly method for creating shortened URLs. // Ajax may refer to: Ajax the Great as a well known hero from the Trojan war and son of Telamon Ajax the Lesser son of the king of Locris, and another hero in the Trojan war Ajax (missionary), Arian missionary who converted the pagan Suevi c. ...
URL obfuscation services There exist redirection services for hiding the referrer using META refresh.
This is very easy to do with PHP, such as in this example.
<?php /* This code is placed into the public domain */ /* Will redirect a URL */ $u=htmlspecialchars($_GET['url']);/* used to sanitise the code*/ ?> <html> <head><title>Redirect</title> <meta http-equiv="refresh" content="0; URL=<?php echo($u); ?>"> </head> <body> You should be able to be redirected to <a href="<?php echo($u); ?>"><?php echo($u); ?></a>. </body></html> This code can then be accessed by example, http://example.org/redirect.php?url=http://www.google.com If the input is not sanitized (using htmlspecialchars()) someone could be supplied with a URL that executes some malicious JavaScript appearing to originate from the website hosting the PHP code. Secure input (and output) handling are Secure programming techniques designed to prevent vulnerabilities or the exploitation of them. ...
See also - For URL redirection on Wikipedia, see Wikipedia:Redirect.
Link rot is the process by which links on a website gradually become irrelevant or broken as time goes on, because websites that they link to disappear, change their content or redirect to new locations. ...
References - ^ Google's serious hijack problem
- ^ Stop 302 Redirects and Scrapers from Hijacking Web Page PR - Page Rank
- ^ Anti-Phishing Technology", Aaron Emigh, Radix Labs, 19 January 2005
External links The Open Directory Project (ODP), also known as dmoz (from , its original domain name), is a multilingual open content directory of World Wide Web links owned by Netscape that is constructed and maintained by a community of volunteer editors. ...
This article is about electronic spam. ...
// A possible 19th century mass telegraph In the late 19th Century Western Union allowed telegraphic messages on its network to be sent to multiple destinations. ...
The Network Abuse Clearinghouse assembles data on what its sponsors see as misuse of the Internet. ...
For other senses of this word, see protocol. ...
E-mail spam, also known as bulk e-mail or junk e-mail is a subset of spam that involves sending nearly identical messages to numerous recipients by e-mail. ...
Address munging is the practice of disguising, or munging, an e-mail address to prevent it being automatically collected and used as a target for people and organizations who send unsolicited bulk e-mail. ...
Bulk email software is software that is used to send email in large quantities. ...
Dictionary spamming is a spamming technique where spammers attempt to guess E-mail addresses by using a dictionary attack based on adding plausible names as prefixes to known domain names. ...
A Directory Harvest Attack or DHA is a technique used by spammers in an attempt to find e-mail addresses. ...
A DNS Blacklist, or DNSBL (definition below), is a means by which an Internet site may publish a list of IP addresses that some people may want to avoid and in a format which can be easily queried by computer programs on the Internet. ...
A spambot is a program designed to collect, or harvest, e-mail addresses from the Internet in order to build mailing lists for sending unsolicited e-mail, also known as spam. ...
A pink contract is an agreement between an email spammer and his Internet service provider. ...
An auto-dialer is an electronic device that can automatically dial telephone numbers to communicate between any two points in the telephone, mobile phone and pager networks. ...
Flyposting is the act of placing advertising posters or flyers in illegal places. ...
Junk faxes are unsolicited advertising via fax transmission. ...
Messaging spam, sometimes called SPIM, is a type of spam targeting users of instant messaging services. ...
Newsgroup spam is a type of spam where the targets are Usenet newsgroups. ...
Telemarketing office Telemarketing is a method of direct marketing in which a salesperson uses the telephone to solicit prospective customers to buy products or services. ...
VoIP spam, also called vamming, is the proliferation of unwanted, automatically-dialed, pre-recorded phone calls using Voice over Internet Protocol (VoIP). ...
To prevent e-mail spam, both end users and administrators of e-mail systems use various anti-spam techniques. ...
Disposable e-mail addressing (DEA) refers to an alternative way of sharing and managing e-mail addressing. ...
Ensuring a valid identity on an e-mail has become a vital first step in stopping spam, forgery, fraud, and even more serious crimes. ...
SORBS (Spam and Open Relay Blocking System) is a controversial open proxy and open mail relay DNSBL. It has been augmented with complementary lists that include various other classes of hosts, allowing for customized email rejection by its users. ...
SpamCop is a free spam reporting service, allowing recipients of unsolicited bulk email (UBE) and unsolicited commercial email (UCE) to report the offense to the senders Internet Service Provider (ISP), and sometimes their web host. ...
The Spamhaus Project is a volunteer effort founded by Steve Linford in 1998 that aims to track e-mail spammers and spam-related activity. ...
List poisoning is a tactic for detecting or diverting e-mail spammers by tricking them into including invalid addresses into mailing lists. ...
Bayesian spam filtering (pronounced Bays-ee-en, IPA pronunciation: , after Rev. ...
Spamdexing or search engine spamming is the practice of deliberately creating web pages which will be indexed by search engines in order to increase the chance of a website or page being placed close to the beginning of search engine results, or to influence the category to which the page...
Keyword stuffing is considered to be an unethical Search engine optimization (SEO) technique. ...
Example of a Google bomb. ...
This article does not cite any references or sources. ...
On the World Wide Web, a link farm is any group of web pages that all hyperlink to every other page in the group. ...
A webring in general is a collection of websites from around the Internet joined together in a circular structure. ...
To meet Wikipedias quality standards, this article or section may require cleanup. ...
Doorway pages are web pages that are created for spamdexing, this is, for spamming the index of a search engine by inserting results for particular phrases with the purpose of sending you to a different page. ...
Link spam (also called blog spam or comment spam) is a form of spamming or spamdexing that recently became publicized most often when targeting weblogs (or blogs), but also affects wikis (where it is often called wikispam), guestbooks, and online discussion boards. ...
Sping is short for ping spam. Pings are messages sent from blog and publishing tools to a centralized network service (Ping Server) providing notification of newly published posts or content. ...
This article does not cite any references or sources. ...
Spam in blogs (also called simply blog spam or comment spam) is a form of spamdexing. ...
Referer spam is a kind of spamdexing (spamming aimed at search engines). ...
The term Internet fraud generally refers to any type of fraud scheme that uses one or more online services - such as chat rooms, e-mail, message boards, or Web sites - to present fraudulent solicitations to prospective victims, to conduct fraudulent transactions, or to transmit the proceeds of fraud to financial...
An advance-fee fraud is a confidence trick in which the target is persuaded to advance relatively small sums of money in the hope of realizing a much larger gain. ...
A typical lottery scam begins with an unexpected email notification that You have won! a large sum of money in a lottery. ...
Make money fast is a title of an electronically forwarded chain letter which became so infamous that the term is now used to describe all sorts of chain letters forwarded over the Internet, by e-mail spam or Usenet newsgroups. ...
Microcap stock fraud, also known as microcap fraud, is a form of securities fraud involving stocks of microcap companies, generally defined as having a market capitalization of under $250 million. ...
An example of a phishing email, disguised as an official email from a (fictional) bank. ...
There are very few or no other articles that link to this one. ...
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