[e2e] RFI: Microsoft accused of TCP standards violation

[David P. Reed]

The following was shared with me and is making the rounds on 
slashdot.   Before I do the work to verify/refute this, has anyone from e2e 
any input?   I'm personally slightly skeptical that this is correct (though 
of course I'd be really concerned if it were).
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Interesting... Microsoft is using TCP/IP in a way that
makes IE respond faster to IIS and slower to non-IIS
webservers:
 > http://grotto11.com/blog/?+1039831658
Could someone with IE and IIS please verify this? A dump of
TCP/IP
traffic with different versions of IE and IIS would be
ideal.
Of course covered on Slashdot:
 > http://slashdot.org/article.pl?sid=03/01/05/2025254
This post sums things up:
The parent +5 post is flat out wrong. This is not about
persistant connections, which is a high-level HTTP feature
that keeps a connection open so that the browser can send
more requests. This is about a low-level TCP hack that IE
uses to get a small speed boost on IIS servers, while
breaking TCP standards compliance.
If I read the article correctly, instead of creating a new
TCP connection and then sending a request, IE sends the
request immediately without bothering to finish the TCP
handshake. Microsoft IIS web servers deal with it
automatically, and it is faster because it saves a
round-trip wait for the ACK and the following requset.
The down side is that non-IIS servers have no clue what this
incoming packet is. It must be invalid because it is not a
SYN. So it gets thrown away, and the server might or might
not reset the connection. If a non-IIS server resets the
connection, IE goes with a standard TCP handshake and has
wasted only the round trip time for the request packet and
the RST. But if the server swallows the invalid packet and
does not send a RST, then Internet Explorer will just sit
around for a few seconds until it times out and falls back
to a standard TCP conection.
The summary is that IE is breaking the TCP protocol for a
small speed boost when connecting to IIS servers. It results
in a small speed penalty when connecting to most non-IIS
servers. When connecting to non-IIS servers that do not
reset the connetion, it results in a very noticable delay.
It could also be a potential security risk, because if this
is true, then it makes it very easy to IP-spoof a HTTP
request against IIS (since the request is a self-contained
packet instead of a long connection sequence).