Date: Mon, 29 Jan 1996 15:11:06 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: davidg@Root.COM Cc: hackers@freebsd.org Subject: Re: Why RFC1323 is disabled on freefall and freebsd.cdrom.com ? Message-ID: <199601291411.PAA05532@labinfo.iet.unipi.it> In-Reply-To: <199601291134.DAA00305@Root.COM> from "David Greenman" at Jan 29, 96 03:33:41 am
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> >1) extensions (really, TCP options) are negotiated. If the server > > does _not_ request for possibly unknown extensions, but merely > > respond to incoming requests, I do not see how this could do > > any harm. I don't know if FreeBSD requests for extensions even > > in the LISTEN state, but disabling this should require trivial > > changes to the kernel (and it would probably be a good idea to > > implement such a behaviour). > > The problem isn't the negotiation - this happens just fine. The problem is > with certain terminal servers that won't pass packets with TCP options in > them. The options negotiation succeeds, but all the packets from that point on > are dropped. For the negotiation to succeed it requires an RFC1323 client, which sends a packets _with options_ asking for whatever extension he wants, the reply _with options_ should go through, and only at this point you have a failure. This means that the (potential) failure rate is going to increase with time, as the number of RFC1323 clients increases and "certain terminal servers" are not upgraded because nobody realizes the problem. Anyways, as I said in my previous email, your policy is perfectly reasonable and denotes great care towards customer satisfaction. > >Note however that the two sites that do use RFC1323 are large > >servers, comparable (or larger) to ftp.cdrom.com. And the second > >one is a commercial site, so they are quite interested in letting > >everybody in without troubles. > > Yes, but wcarchive is the largest FTP site in the world. We likely have 10 > times the traffic (or more!) of those other sites. I don't think you realize > just how much traffic wcarchive has each day. I don't question your word. I just want to point out that people at unix.hensa.ac.uk (and wwwcache.hensa.ac.uk, a national web proxy) say that they serve over 1 million web documents per day, so they might have scalability and interoperability problems similar to yours. Two differences, perhaps: * www documents are often smaller than ftp, and just one per connection, so it's hard to make a comparison of the traffic; * they mostly serve UK clients, so they might have a different view of the world (read: thei might not have to deal with the same brokenesses). Luigi ==================================================================== Luigi Rizzo Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it Universita' di Pisa tel: +39-50-568533 via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 http://www.iet.unipi.it/~luigi/ ====================================================================
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