IEInternals

A look at Internet Explorer from the inside out. @EricLaw left Microsoft in 2012, but was named an IE MVP in '13 & an IE userAgent (http://useragents.ie) in '14

Browse by Tags

Tagged Content List
  • Blog Post: URL Length Limits

    Today’s question is a simple one: “What is the maximum URL length supported by Internet Explorer?” And the answer, as befitting an IEInternals post, is surprisingly complicated. The simplistic answer is that WinINET.h defines INTERNET_MAX_URL_LENGTH as 2083 characters, and this...
  • Blog Post: RFCs for HTTP/1.1 Updated

    After years of effort, the HTTPBIS working group of the IETF has completed revisions of the venerable RFC2616 that defines the HTTP/1.1 protocol. These revisions clarify ambiguous sections of the original, deprecate problematic features, and reflect real-world implementation experiences. There’s...
  • Blog Post: Browser Arcana: IP Literals in URLs

    While virtually all web traffic flows over connections based on the Internet Protocol, most of the time your browser first uses DNS to look up the target hostname’s IP address. However, sometimes URLs directly specify an IP address, skipping DNS altogether. When an IP appears directly within such...
  • Blog Post: What I’d like to see in IE12

    As the holidays approach, I’ve decided to publish my “wishlist” for the next version of Internet Explorer. I’ve been pretty good this year, so hopefully the IE team will deliver some of these presents. :-) Please remember: I’m just an MVP, and I don’t have any magic...
  • Blog Post: IE11 Changes

    In the past, I’ve published “Minor changes” lists for IE9 and IE10 . The goal of those lists was to briefly document changes that might not be recorded elsewhere. This time around, I’m aiming to provide broader coverage of changes in IE11, including major new features and APIs...
  • Blog Post: Braindump: DNS

    Note: The “brain dump” series is akin to what the support.microsoft.com team calls “Fast Publish” articles—namely, things that are published quickly, without the usual level of polish, triple-checking, etc. I expect that these posts will contain errors, but I also expect...
  • Blog Post: Proxy-Authentication breaks many applications

    When I first joined Office, I worked on the team responsible for delivering Help, Templates, and ClipArt into the client applications. As we were testing our work in various simulated customer environments, we found a big problem. At least one big customer (tens of thousands of licenses) had a network...
  • Blog Post: Networking Improvements in IE10 and Windows 8

    Internet Explorer 10’s networking code builds upon the performance improvements in IE9 ( caching , overall networking ) to help ensure that IE10 loads pages as quickly as possible. In IE10, we identified a few key areas for improvement based on customer feedback, code inspection, and telemetry...
  • Blog Post: Content-Length and Transfer-Encoding Validation in the IE10 Download Manager

    Back in March of 2011 , I mentioned that we had encountered some sites and servers that were not sending proper Content-Length headers for their HTTP responses. As a result, we disabled our attempt to verify Content-Length for IE9. Unfortunately, by April, we’d found that this accommodation...
  • Blog Post: Brain Dump: International Text

    Note: The “brain dump” series is akin to what the support.microsoft.com team calls “Fast Publish” articles—namely, things that are published quickly, without the usual level of polish, triple-checking, etc. I expect that these posts will contain errors, but I also expect...
  • Blog Post: The Intranet Zone

    Internet Explorer maps web content into one of five security zones. After the Local Machine Zone, the Local Intranet Zone is probably the most misunderstood of the Zones, and is a common source of confusion and compatibility glitches. Mapping into the Local Intranet Zone For the Trusted and Restricted...
  • Blog Post: Use IMG tags only for Images

    First, a bit of background. When web developers are optimizing the performance of their sites, often they try to use their homepage to pre-cache resources that will be used on later pages. They might do so by kicking off "pre-fetch" resource downloads after the content required by the homepage itself...
  • Blog Post: Pushing the Web Forward with HTTP/308

    Recently, the IESG approved publication of a new Internet-Draft defining the HTTP/308 status code (Intended Status: Experimental). This status code is defined as the "Permanent" variant of the existing HTTP/307 status code. Recall that HTTP/307 was defined back in 1999 to remove the ambiguity around...
  • Blog Post: Understanding Enhanced Protected Mode

    Last week, Andy Zeigler announced the introduction of Enhanced Protected Mode (EPM) over on the IEBlog. In today’s post, I’d like to provide further technical details about EPM to help security researchers, IT professionals, enthusiasts, and developers better understand how this feature works...
  • Blog Post: Download Resumption in Internet Explorer

    While most file downloads are quickly and successfully completed, some large downloads take a long time to complete, and may be interrupted in the middle by either the user choosing to “Pause” or due to networking glitches (e.g. WiFi connection dropped). One of the significant...
  • Blog Post: Detecting Captive Network Portals

    Over on SuperUser , there’s a great explanation of how Windows determines whether a newly-connected network has a proper Internet connection, or whether the user should open a browser to login or click through a Terms of Use agreement. The general idea is that Windows will attempt to download a...
  • Blog Post: HTTPS and Keep-Alive Connections

    As we explore network performance on the “real-world web”, one bad pattern in particular keeps recurring, and it’s not something that our many IE9 Networking Performance Improvements alone will resolve. The bad pattern is the use of Connection: close semantics for HTTPS connections...
  • Blog Post: Misbehaving HTTPS Servers impair TLS 1.1 and TLS 1.2

    Back in the summer of 2009, I blogged about Windows 7’s new support for TLS 1.1 and TLS 1.2 . These new protocols are disabled by default, but can be enabled using Group Policy or the Advanced Tab of the Internet Control Panel: Some adventurous Internet Explorer users have found that...
  • Blog Post: File Upload and Download Limits

    Over the last few years, we’ve had a few questions about WinINET’s limits for file upload and download. I’ve summarized those limits in the following table: Upload (total size) Download (per file) Internet Explorer 6 2gb 2gb...
  • Blog Post: Content-Length in the Real World

    Earlier in IE9 , we tried to change the WinINET networking component to reject as incomplete any HTTP responses for which the Content-Length header specified more bytes than the server actually sent back. It turns out that some sites and applications expect to be able to specify an incorrect Content...
  • Blog Post: Challenge-Response Authentication and Zero-Length Posts

    From time-to-time, web developers contact the IE team reporting that they’ve encountered a problem whereby Internet Explorer submits a POST but fails to transmit the content body. This bodyless POST indicates via the Content-Length header that the POST is zero-bytes long, regardless of how much...
  • Blog Post: SOCKS Proxies in Internet Explorer

    We recently had a report over on the IEBlog that SOCKS proxies are not supported by IE9 Beta. That observation is correct, and a regression from prior versions of Internet Explorer; IE9 Beta simply ignores the SOCKS proxy if one is specified in the Internet Control panel. Update: This regression,...
  • Blog Post: Understanding Conditional Requests and Refresh

    Today's post is a collection of technical tidbits about conditional HTTP requests and the behavior of IE's Refresh button. It's probably of limited interest to most readers, but if you need to deeply understand either of these topics, hopefully you will find it helpful! Conditional Requests Web...
  • Blog Post: The Performance Impact of META REFRESH

    Some sites will utilize the META REFRESH directive to perform a client-side redirection. In general, this should be avoided in favor of other redirection types, for instance, a server-side redirection (HTTP/3xx) or by using JavaScript. Using META REFRESH creates a potential performance problem in IE...
  • Blog Post: HTTPS Caching and Internet Explorer

    From time-to-time, I get questions about Internet Explorer’s behavior when it comes to caching of HTTPS-delivered content. It comes as a surprise to many that by-default, all versions of Internet Explorer will cache HTTPS content so long as the caching headers allow it . If a resource is sent...
Page 1 of 2 (35 items) 12