Path: utzoo!utstat!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!intercon!amanda@intercon.com From: amanda@intercon.com (Amanda Walker) Newsgroups: news.software.nntp Subject: Re: Suggested NNTP enhancements for user access control Message-ID: <1546@intercon.com> Date: 11 Nov 89 20:12:00 GMT References: <10095@ucsd.Edu> <1802@gazette.bcm.tmc.edu> <1544@intercon.com> Sender: news@intercon.com Reply-To: amanda@intercon.com (Amanda Walker) Lines: 32 In article , bob@MorningStar.Com (Bob Sutterfield) writes: > In article <1802@gazette.bcm.tmc.edu>, sob@watson.bcm.tmc.edu (Stan Barber) writes: > One other thing that has been suggested are a TIME command to get > the server's current view of time. > > What about transmission delay, and all the other things that you have > to worry about if you're even going to bother starting to think about > time synchronization? You might as well invent a time protocol... > [ lots of good stuff about NTP ] This, of course, does address the problem quite handily. One of the reasons I used the approach I did in some prototype software (which turned out to be unnecessary for completely unrelated reasons) is that the NEWNEWS and NEWGROUPS commands take magic cookies (times) as arguments but give you no way to obtain them except by hoping your clocks are in sync. The only reason that figuring out the server's idea of the time works at all is that NNTP currently gives you a static view of the news base (i.e. what's there when a session starts up). My eventual approach was to ignore NEWNEWS and NEWGROUPS. It was faster to just parse the active file, which gave me the information I needed without having to do anything funky. However, passive NNTP feeds use NEWNEWS and NEWGROUPS, so the problem isn't completely amenable to workarounds within the NNTP protocol itself. NTP is probably the way to go. I wonder if a lonely standalone network (like ours :-)) could run NTP and sync up by modem with an NBS (or is it NIST these days?) modem-equipped cesium clock every so often? That could be nifty... (especially when said clock is only a local call :-)). -- Amanda Walker