Date: Mon, 29 Jan 1996 12:18:42 +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: <199601291118.MAA05320@labinfo.iet.unipi.it> In-Reply-To: <199601291004.CAA29539@Root.COM> from "David Greenman" at Jan 29, 96 02:03:47 am
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> >I was wondering why RFC1323 timestamps are disabled on both freefall
> >and freebsd.cdrom.com
> >
> >I know one reason not to have them is that they defeat VJ header
> >compression, but I don't see the point in having them disabled on
> >freebsd.cdrom.com
> >
> >If there are no good reasons, could they be enabled ?
>
> It is disabled on both machines because they are public FTP/WWW servers,
> and RFC1323 (and other TCP extensions) don't work for all people.
> It will remain disabled until such time that 99.999% of the people out
> there can deal with TCP extensions. Otherwise, we'll be getting way too many
> bug reports. Wcarchive, for example, serves 20000 people a day; I'm sure you
> can imagine the extremely high probability that more than one person per day
> will run into this problem. :-)
All the above is mostly reasonable, and of course I cannot object
to this policy.
I just want to point out a few things, which I hope will make you
change your positions for the long term.
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).
2) the "99.999%" may be an exaggeration, but to me it means "never".
This might be a bad idea for more useful options (such as
selective ACKs).
3) I have done a quick investigation on the few ftp sites which came
to my mind (I don't use much ftp these days...) and here is the
result:
RFC1323 enabled:
unix.hensa.ac.uk
ftp.netscape.com
RFC1323 disabled:
ftp.cdrom.com
funic.funet.fi
ftp.ncsa.uiuc.edu
sunsite.unc.edu
I did not expected many sites to support RFC1323, as they might
even be not present in older OS revisions etc.
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.
Thanks
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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