Is this why I sometimes get mail that is two days or more old even though= we=20 do not use IE? > > Subject: MS changes IE and IIS TCP/IP rules > Date: Sun, 5 Jan 2003 17:13:14 -0800 (PST) > From: Matt Alexander > To: PLUG-AZ > > Interesting... Microsoft is using TCP/IP in a way that makes IE respon= d > 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=3D03/01/05/2025254 > > 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 connectio= n > 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 connect= ion > 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 thro= wn > 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 pack= et > and the RST. But if the server swallows the invalid packet and does no= t > send a RST, then Internet Explorer will just sit around for a few seco= nds > 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 pena= lty > when connecting to most non-IIS servers. When connecting to non-IIS > servers that do not reset the connetion, it results in a very noticabl= e > delay. > > It could also be a potential security risk, because if this is true, t= hen > it makes it very easy to IP-spoof a HTTP request against IIS (since th= e > request is a self-contained packet instead of a long connection > sequence). > > > --------------------------------------------------- > PLUG-discuss mailing list - PLUG-discuss@lists.plug.phoenix.az.us > To subscribe, unsubscribe, or to change you mail settings: > http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss > > ------------------------------------------------------- --=20 :-)~Mike~(-: