Please, Should I forwad this to my ISP? ---------- Forwarded Message ---------- 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 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=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 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 connectio= n 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 second= s 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 penalt= y 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, the= n 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). --------------------------------------------------- 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~(-: