Please Whitelist This Site? I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :) If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads. If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK. Thanks for your understanding! Sincerely, Charles Kozierok Author and Publisher, The TCP/IP Guide

NOTE: Using software to mass-download the site degrades the server and is prohibited. If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.

The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  TCP/IP Key Applications and Application Protocols            9  TCP/IP Application Layer Addressing: Uniform Resource Identifiers, Locators and Names (URIs, URLs and URNs)                 9  Uniform Resource Locators (URLs)

URL Relative Syntax and Base URLs 1 2 3 4 URL Obscuration, Obfuscation and General Trickery

Explicit URL Delimiting and URL Redirectors

To resolve both the wrapping and delimiting problems, a special URL “super-syntax” is sometimes employed, especially when URLs are used in other text. This is done by surrounding the URL in angle brackets, possibly including the label “URL:”. before the scheme name. For example, all of the following are equivalent:

http://www.networkingistoodarnedcomplicated.com

<http://www.networkingistoodarnedcomplicated.com>

<URL:http://www.networkingistoodarnedcomplicated.com>

The angle brackets indicate clearly where the URL begins and ends, making it easier for both programs and humans to deal with long URLs.

Another solution sometimes used for long URLs are redirection services, provided by many Web sites. For example, http://www.tinyurl.com is a free service that allows someone to create a short URL that automatically loads a resource at a much longer URL.

One final issue I want to discuss isn't related directly to long or complex URLs, but is related indirectly to the matter of length: URL abbreviation. Many people use URLs so often that they become, well, lazy when it comes to specifying URLs. They tend to leave off portions of the full URL syntax to save time and energy. I don't mean by this that they specify relative URLs, but rather, they specify absolute URLs with “missing pieces”.

For example, rather than type “http://www.sitename.com”, they might type “http:www.sitename.com”, leaving off the two slashes. More commonly, people omit the scheme name entirely, just entering “www.sitename.com”. Technically, this is not a URL, it is just a domain name. However, most Web browsers can handle this, assuming by default that the scheme is “http://” if none is provided. (Don’t feel bad, I do it too! J)

URL Relative Syntax and Base URLs 1 2 3 4 URL Obscuration, Obfuscation and General Trickery