[NTLUG:Discuss] why does the web site cannot be 'see' fromoutside (internet)?

[m m]

>From: MadHat <madhat at unspecific.com>
>Reply-To: discuss at ntlug.org
>To: NTLUG-Discuss <discuss at ntlug.org>
>Subject: Re: [NTLUG:Discuss] why does the web site cannot be 'see' 
>fromoutside (internet)?
>Date: 07 Jan 2003 06:55:54 -0600
>
>On Mon, 2003-01-06 at 13:23, Greg Edwards wrote:
> > m m wrote:
> > >
> > >
> > > the problem still happend even I can see the ip A record changed 
>(which
> > > means that Public DNS _really_ updated my A record)
> > >
> > > How/what the problem will happen if the serial number don't change?
> > > How TTL works on DNS on real world?
> > >
> > >
> > >>
> > >> Is it possible that the DNS was not reloaded or not updated in a
> > >> reasonable period so the new IP was not broadcast for awhile?
> > >
> > > at where? on my box? not quite understand this one.
> > >
> >
> > A change in the serial number will force an expire of a record even if
> > the TTL has not expired.  Just cause you change the values in a DNS file
> > does not mean that named will read them.  If your admin does not change
> > the serial number or does not tell named to re-read the files no new IPs
> > will get sent out to the world.

according to Madhat said (see below), if the serial number not changed, it 
will not send out to the word even you re-read/re-start/reload the named? 
right?


>
>The serial number HAS to be incremented for DNS to be updated if you are
>using BIND.  It will not even bother looking at the rest of the file if
>the serial has not changed.  The TTL is not for the local machine (the
>one serving DNS) it is for the remote machine and how often they should
>retain records before checking for updates.  These remote machines don't
>really care about the serial directly.

so, the remote machine holds the domain information, after ttl expired, it 
go back to look again, and when the remote machine see the serial number 
does not change, then it stops and assumes the ip stays the same? and if the 
remote machine sees the serial number has been changed, the it goes on 
reading all the infrmation and updates the new records (in this case new 
ip)?

>
>--
>MadHat at Unspecific.com
>`But I don't want to go among mad people,' Alice remarked.
>`Oh, you can't help that,' said the Cat: `we're all mad here...'
>    -- Lewis Carroll - _Alice's_Adventures_in_Wonderland_
>
>_______________________________________________
>https://ntlug.org/mailman/listinfo/discuss


_________________________________________________________________
Protect your PC - get McAfee.com VirusScan Online 
http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963