|Why does WebTV use proxy servers?
Proxy servers allow WebTV to speed up users' Web sessions. By
caching web content, proxies can deliver popular pages without needing to retrieve a
unique copy from the Internet each time. Additionally, the proxy server can
"tweak" individual pages to ensure that they will display properly on a
What is this
To speed the download of pages, the proxy will optimize image and
audio formats in addition to the HTML before sending the Web page and associated files
along to a WebTV terminal. This process does not result in a visible alteration of Web
What version of HTTP does WebTV
WebTV's servers implement HTTP 1.0, with
selected parts of 1.1.
Are all web pages cached?
No. The following types of pages will not
- Pages that are passed through an SSL(secure) connection
- Pages that have an associated cookie
- Any page that does not contain a "last modified"
date and an explicit "expires" date
How do I keep my pages from being
The most reliable way to keep pages from being cached by proxy
servers is to alter your server configuration files. However, most Webmasters do not have
access to these files, so the use of <meta> tags to emulate HTTP headers is common.
WebTV proxy servers, unlike most other proxies, will honor
"no-cache" directives given in this fashion.
There are several different ways of writing a
"no-cache" meta tag, and all of them are seen on Web pages. There is no harm in
inserting multiple <meta> tags within a document, but some are more useful than
HTTP-EQUIV="Expires" CONTENT="Thu, 01 Dec 1994 16:00:00 GMT">
The most reliable
method of ensuring that your content is not cached comes directly from the HTTP spec. This meta
tag specifies an "expires" field that has already passed. Thus, the proxy will
not cache the content. Current WebTV proxies will honor this header.
A popular way of
specifying a date in the past is to specify the date as "0". While this will
work, Webmasters should note that it is not strictly "correct", and HTTP 1.0
servers are under no obligation to honor tags formed in this way. Current
WebTV proxies will honor this header.
|This method of specifying a "no cache"
directive to a proxy server came about in HTTP 1.1. WebTV will be supporting this in the
next upgrade of its proxy servers. Current WebTV proxies will honor this header.
|This meta tag is also commonly seen, although it
is incorrect for a server to send this to a client. HTTP 1.0 specifies "pragma"
as a header to be sent by clients when requesting a fresh copy of a page, not by
servers. However, due to its widespread use, WebTV will support this header in the next
upgrade of its proxy servers. Current WebTV proxies will honor this header.
users have static IP addresses?
To speed surfing, a WebTV terminal may issue requests through a
number of proxies; anywhere from two to a a dozen. This results in a correspondingly large
number of IP addresses for a single WebTV user during a single session for
non-secure connections. If a connection is made through SSL, the WebTV user will
bypass the proxy and have a static IP until an HTTP connection is resumed. Since the Web
is primarily stateless,
multiple IP numbers are rarely a problem. However, if your site requires users to maintain
a static IP address during their non-secure sessions, please send an email to staticIP@webtv.net.This address is only valid for
Webmasters who need this service.