WebTransports's WebLog : Kernel Http

Migrating

WebTransports — Wed, 20 Jul 2005 00:21:00 GMT

This blog is migrating to the WNDP blog. This one will stick around but won't be updated.

David Wang discusses http.sys's kernel response cache.

WebTransports — Fri, 15 Jul 2005 03:43:00 GMT

Check out David Wang's recent post about http.sys's response cache. He describes the configurable registry keys and how the scavanger works.

Http.sys makes the news (not in a good way)

WebTransports — Thu, 24 Feb 2005 19:40:00 GMT

InformationWeek has an article about a reliability update posted to Windows Update for http.sys. The problem was that http.sys plus a recent update to a certain vendor's anti-virus software leads to a blue screen. Because of the type of failure, it took a while for the Windows Error Reporting crashes to get debugged back to us. We released a fix for the bug and attached it to the Error Reporting bucket. This meant that after the crash occured and you reported it to Microsoft, the UI would inform you of a patch, and let you install it. Still the crashes continued to come in, in bigger numbers. It was time to do something more, so we decided that the best thing for our customers was to get it released on windows update for everyone.

IIS/Http.sys Webcasts

WebTransports — Sat, 22 Jan 2005 03:36:00 GMT

Chris Adams, a technical lead in IIS, has a series of webcasts about IIS and Http.sys.

HTTP.SYS + .Net Framework 2.0 + !IIS -> ASP.NET

WebTransports — Sat, 20 Nov 2004 03:29:00 GMT

Aaron Skonnard has an MSDN Magazine article about running ASMX without IIS, but instead uses Http.sys through the new managed HttpListener APIs in the .NET Framework 2.0. He provides code demonstrating how to tie Http.sys directly to ASP.NET.

IIS Team blog and Server Caching

WebTransports — Wed, 17 Nov 2004 20:35:00 GMT

IIS now has a team blog called IIS Hints & Tips. Thier first technical post is about how IIS and ASP.NET uses the http.sys cache.

HTTP in the Event Log on XPSP2

WebTransports — Tue, 12 Oct 2004 02:22:00 GMT

Thoose who are really looking might have found the following event in your event log:

Reservation for namespace identified by URL prefix http://*:2869/ was successfully added.

This is just UPNP reserving it's port and namespace in http.sys.

Okay... a little more ego inflating

WebTransports — Wed, 06 Oct 2004 19:50:00 GMT

Well, this is meant to be a more technical blog, and I got in my mini ra-ra post yesterday, but I was happy to see Mary Jo Foley pointing to this eWeek article, "IIS Rounds the Security Corner". I've personally been at Microsoft from five years now and I've watched and participated in Microsoft's efforts to make security a fundamental part of the software engineering process. It's still a continuing effort, as Internet Explorer shows, but we have made even more progress since Windows 2003 as demonstrated in the springboards in XPSP2 and further improvements in our methods such as the static code analysis tools and a maturing Threat Modelling process.

There have been application compatability costs to some of our choices, such as described step 11 in this Pre-Post IIS6 Installation task list: "There are limits on the url content, url segment length, client submission size, etc. Also HTTP.sys strictly enforces http 1.1 and 1.0 standards. If you have a monitoring system delivering sloppy requests to IIS 6, those may get rejected and there is no "AcceptSloppyHTTP" registry settings." I will try to write an entry on what some of the gotcha's a few of our customers have seen.

Most Reliable Hosting Providers

WebTransports — Tue, 05 Oct 2004 19:10:00 GMT

Netcraft reports that in September three of the top 10 most reliable hosting providers during September were running Windows 2003 and IIS6, Netcetera, DataPipe and myhosting.com. Another three were running Windows 2000, including the top of the rankings Energis.

Update: Forgot to add the netcraft source link.

SQL Server 2005 uses http.sys

WebTransports — Fri, 06 Aug 2004 23:11:00 GMT

Peter DeBetta in a developer.com article demonstrates how to use SQL Server 2005 to create HTTP endpoints:

So what is an HTTP Endpoint? You may have heard that it is SQL Server 2005's means for creating Web services, but it actually is much more. An HTTP Endpoint also is a means of creating interfaces via HTTP or TCP for SOAP, T?SQL, Service Broker, and even database mirroring. Although these other functions are very intriguing, this discussion concerns only the ability to create Web services in SQL Server—Web services that can return rowset data, scalar values, messages, and even errors, all of which are serialized into XML automatically. And, an HTTP Endpoint does all of this without requiring you to install IIS (it uses the Windows 2003 kernel module http.sys).

...

CREATE ENDPOINT SQLEP_AWProducts
    STATE = STARTED
AS HTTP
(
    PATH = '/AWproducts',
    AUTHENTICATION = (INTEGRATED),
    PORTS = (CLEAR),
    SITE = 'win2k301'
)
FOR SOAP
(
    WEBMETHOD 'ProductList'
        (NAME='AdventureWorks.dbo.prProductList'),
    WEBMETHOD 'ProductStockInfo'
        (NAME='AdventureWorks.dbo.prProductStockInfo'),
    WEBMETHOD 'ProductPhoto'
        (NAME='AdventureWorks.dbo.fnProductPhoto'),
    BATCHES = DISABLED,
    WSDL = DEFAULT,
    DATABASE = 'AdventureWorks',
    NAMESPACE = 'http://Adventure-Works/Products'
)

Http.sys and the XPSP2 Firewall

WebTransports — Mon, 02 Aug 2004 21:07:00 GMT

Larry Osterman of the WMC Team has a three part blog series about what he needed to allow http.sys to open ports and get through the Windows XP SP2 firewall.
Part 1 | Part 2 | Part 3

Http.sys's HTTPERR and Timer_ConnectionIdle

WebTransports — Thu, 15 Jul 2004 21:27:00 GMT

For all those IIS6 or other http.sys users out there, you might have noticed the HTTPERR logs. If you haven’t it’s over in %SystemRoot%\system32\LogFiles\HTTPERR\httperr*.log. It’s a log of anything that http.sys does with connections and requests that user mode didn’t tell us directly to do. There is a nice KB article with a lot of information about the HTTPERR log. Here is what it looks like:

2002-07-05 18:45:09 172.31.77.6 2094 172.31.77.6 80 HTTP/1.1 GET /qos/1kbfile.txt 503 – ConnLimit
2002-07-05 19:51:59 127.0.0.1 2780 127.0.0.1 80 HTTP/1.1 GET /ThisIsMyUrl.htm 400 – Hostname
2002-07-05 19:53:00 127.0.0.1 2894 127.0.0.1 80 HTTP/2.0 GET / 505 - Version_N/S
2002-07-05 20:06:01 172.31.77.6 64388 127.0.0.1 80 - - - - - Timer_MinBytesPerSecond

If you have a look at one running on a real life web server, it’s usually a lot of entries with the reason Timer_ConnectionIdle entries and a number of entries with the reason Url. The reason code Url entries are often from security software scanning for vulnerable hosts or worms that take advantage of sloppy Url parsing trying to spread. These requests just get rejected outright by http.sys’s pretty strict validation checks and we log that rejection here. The other reason code, Timer_ConnectionIdle, happens in normal HTTP protocol usage, where the client decides not to disconnect from the server because there is a good chance that it will have another request for the server either in the process of loading a page or because a client will probably click a link on a web page that will go back to the same server. By default the server will close the connection and reclaim those resources after 2 minutes of inactivity. This is nothing to worry about, it's just an informational type of entry.

Don Box writes some HTTP.SYS code

WebTransports — Wed, 31 Mar 2004 03:51:00 GMT

Don Box is playing with HTTP.SYS via the new Whidbey managed framework on Windows XP SP2. If you are really sharp looking at the service dependencies, you will find our first user on XP SP2 is UPnP. Don does mention the problem about coexistence of IIS5 (or any other app) and HTTP.SYS on port 80/443; but doesn't mention the one work around we have in place right now. The IP Listen List lets an administrator limit HTTP.SYS to specific interfaces, letting that other conflicting app work in coexistence. It's not as ideal as sharing based on the namespace, but its better then nothing.

Welcome to Window's Web Transports Blog

WebTransports — Wed, 25 Feb 2004 01:01:00 GMT

This is a collaborative Weblog from the Web Transports Team in Windows Networking. As a team we work on the http stacks in Windows; http.sys the kernel part of the IIS 6.0 Web Server (part of Windows Server 2003) and its own developer API, wininet.dll which is the client side HTTP stack at the heart of Internet Explorer, and winhttp.dll which is the client side HTTP stack favored by server applications relying on performance and reliability.

At this point we aren’t sure exactly what sort of information we will put up here, but it probably will be related to whatever we get asked in the comments and whatever we are working on that week. Please don’t hesitate to post a comment with any questions or topics you wish us to talk about in the future. A lot of it will be developer focused, some content will be end user focused (especially on the wininet.dll/IE side).

If you don’t know what an HTTP stack is, it’s a protocol stack that talks the W3C’s HTTP protocol on behalf of applications. That’s the main protocol used on the web. It’s gone through a few versions, from 0.9 to 1.0 and now 1.1. We’ll probably write an entry or point to some good references on what has changed over time in the protocol’s evolution.

By the way, my name is Ari Pernick, and I’m a test development lead for web transports. As we post over time you will get an introduction to some of the Developers, Testers, Program Management, Product Support and others who contribute to our team.

UPDATE: In the comments below I claimed that pipelinning would be in Longhorn Version of Winhttp. It was early in the product cycle and since then, for a number of reasons, the code changes to support pipelinning support didn't make it into the final release. Sorry for any confusion.