Sometimes when I reply to a list message it only goes to the sender. Why is this?
-----Forwarded Message----- From: Robert Fisher <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Subject: Re: Paradise spam + virus filtering Date: 01 Sep 2003 21:07:28 +1200 Shane, how about correcting your time - my emails are sorted by date/time sent so yours are always out of order. On Tue, 2003-09-02 at 03:13, Shane Hollis wrote: > > On Mon, Sep 01, 2003 at 01:49:12PM +0000, Shane Hollis wrote: > > > sigh ... i didn't explain myself fully enough ... my concern is not with > > > lookups but with changes in caches. I have had a number of situations > > > where caching has resulted in DNS changes being a pain in the neck and > > > not propogating correctly. This is especially true when working with > > > overseas clients. > > > > > > To sit on the backbone in the USA gives me a quicker dissemination of > > > changes to DNS entries. The lookups are heirarchical .. this I know, as > > > you have mentioned you look up the closes and work outwards until you > > > find it but caching sometimes mucks this up and so to make changes it is > > > easier to start with the main servers and work down to the smaller > > > servers, not the other way around. > >....> > > I'm afraid I'm with both Nick and David again... > > > > I think you've got yourself all confused, since location has no bearing > > whatsoever on how fast or slow DNS changes take effect... > Yes it does ... the more 'authorative' a dns server the more 'non-authorative' > DNs servers it affects. I explain it more fully in another email. > > At the risk of repeating myself. .... If I change a DNS entry on a server in > my bedroom that affects my domain then the change has to go to another dNS > upstream of me ( maybe my ISP ) then that pushes changes upstream ... until > eventually it hits someone upstream of your ISP (maybe Waikato) who then > tells your isp who then tells you. If I had told the DNS at Waikato then you > would have known faster than me teling my server, or isp or their isp. > > Here is a table of two changes possibilities. I will assume a change time of 1 > hour for refreshing cahes on all machines. I will also asume a worst case > senario where every downstram server queries an upstream server one minute > before the upstream server refreshs its cache. Change time is 00:00 hours. > > There are five servers involved: > My server at home(Me1) > My ISP (Me2) > Waikato (W) > Your ISP (You2) > Your server (You1) > > For me to refresh Me1 and to get changes to you would look like this....no > changes pushed, relies on boradcast requests for changes > > Time Server Time_change_Registers > 00:00 Me1 00:00 > 01:00 Me2 Told by Me1 when asked for changes and queried > my DNS > 02:00 Waikato Changes as asked me2 or me1 > 02:59 you2 Told by waikato when asking for changes > 03:58 You1 Told when asking you2 > > Total time for You1 to change is 3:58:00 > > > For me to refresh Me1 and to get changes to you would look like this....with > changes pushed to other servers > Time Server Time_change_Registers > 00:00 Me1 00:00 > 00:00 you2 No change as asked waikato and waikato didn't > know > 00:01 Me2 00:01 Told by Me1 - I am being generous and > pushing the change > 00:02 W 00:02 Told By Me2 - Waikato is being generous > and pushing a change > 00:59 you1 No change as you have queried You2 > 01:00 you2 Changes as asked Waikato > 01:59 you1 Changes to DNS as you1 asked You2 which is now > changed > > Total time for you1 was 1:59:00 > Total time for me1 was 00:00 > > For me to refresh waikato the change looks like: > Time Server Time_change_Registers > 00:00 W Changed at 00:00 > 00:00 you2 Knows as asked Waikato > 00:59 you1 Knows as asked you2 > > Total time for you2 to change is 00:59 > Half the time in a short chain of change with no pushes of the changes. > > In routing terms you normally push a change to the most authorative server > first and let it filter down from there. If I want to start a rumour I don't > tell Mary Hide at home, I tell Paul I'll broadcast this crud to everyone > Holmes. Same way, if I want to make routing changes or major, world wide > effective DNS changes start in the most authorative place I can ... for me > this would possibly be Pacfic ARIN type server or the US depending on what it > caches and how quickly I want changes to replicate. > > I have changed my domain in the US and been up and running with other clients > receiving changes in less than 15 minutes. It wouldn't happen if I only > changed things at paradise or at home. It all dpepnds on how authorative the > server you are asking and how much you trust their cache.... > > The other factor in all this is the stability and up time of the network ... > the backbone in the US is always up (comparitively), collects more traffic > and is faster. There are more users in the US and more important servers > there. Same thing as spreading the plague. Better off to do it in a crowded > mall in a large density population of a huge city with excellent communting > and many connections than in the corner dairy on Goslow Street, Brunner. > > My numbers above are probably out, I have the headache from hell but they get > the point across. > Hope this clarifies things... -- Robert Fisher www.fisherfamily.orcon.net.nz -- Robert Fisher www.fisherfamily.orcon.net.nz
