Thanks Haim..
> You can flush
> DNS with this command: "ipconfig /flushdns"
I don't have a problem with my own DNS, where I have sovereignity. It's
small enough to simply restart whenever a dynamic change occurs, without
getting 500 people angry all at once.
The problem is with, for instance, NetVision's DNS, which will query me,
then disregard my low TTL setting, and cache my entry for, say, a couple
of days, when the host disconnected from it's dialup, reconnected under a
new IP and updated my DNS. And I can't just *flush* NV's DNS cache..
( Well, actually, I can if I really want to, but that'll probbably get me
in trouble .. paka paka .. what a big h4x0r I am... ;-)
I'll try your suggestion with host-specific TTL settings and see if it
helps any.
Thanks!
---= Miki Shapiro =------------------
---= Cell: (+972)-56-322433 =--------
---= ICQ: 3EE853 =-------------------
---= Windows Programmer in Rehab =---
-------------------------------------
"If at first you don't succeed...
.. Skydiving is probbably not for you."
On Thu, 14 Jun 2001, Haim Gelfenbeyn wrote:
> Miki,
> I'm not exaclty sure about your case, but here is what I did, and it
> works:
> Declare small TTL not for the entire zone, but only for the dynamic PPP
> interface name. Below is part of my own file, with some entries replaced
> with xxx and xxx2 for privacy. Note that 30 secs. TTL is declared only
> for "cerberus", which is dynamic. Others, on my internal network, have
> longer TTLs. I know that at least machines I work from, honour 30 secs
> TTL. (mainly Linuxes and FreeBSDs). I do know what W2K have DNS cache
> which has to be flushed - it does not honour TTLs AFAIK. You can flush
> DNS with this command: "ipconfig /flushdns"
>
> Haim.
>
> --- CUT ---
> $TTL 86400
> @ IN SOA xxx.co.il. admin.xxx.co.il. (
> 200106051 ; serial, todays date+todays
> serial #
> 8H ; refresh
> 2H ; retry
> 1W ; expire
> 1D ) ; minimum
>
> NS ns.xxx2.co.il.
> NS hell.xxx.co.il.
> MX 10 cerberus.xxx.co.il. ; Primary Mail
> Exchanger
> MX 20 mail.xxx2.co.il. ; Secondary Mail Exchanger
>
> cerberus 30 A 212.150.124.222
> tomodem A 10.200.1.3
> orckit A 10.0.0.138
> --- CUT ---
>
> Regards,
> Haim.
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED]] On Behalf Of Miki Shapiro
> > Sent: Thursday, June 14, 2001 4:41 PM
> > To: Shachar Shemesh
> > Cc: Happy Linux Campers
> > Subject: Re: DNS issue
> >
> >
> >
> > On Thu, 14 Jun 2001, Shachar Shemesh wrote:
> >
> > > An ISP places a cache to save on traffic. putting too low
> > an expire time
> > > spoils that.
> > >
> > > A value that should work OK, at least with some cases I've
> > heard of, is
> > > 180 (three minutes). It should still give your client a reasonably
> > > updating service.
> >
> > Tried with 180s and 300s, and it don't work.
> >
> > Can someone explain (or point to some FM to RT) exactly what
> > "refresh",
> > "retry", "expire", and "minimum" in the SOA record of a zone file do?
> >
> > I can't find any decent documentation for this.
> >
> > Thanks!
> >
> > ---= Miki Shapiro =------------------
> > ---= Cell: (+972)-56-322433 =--------
> > ---= ICQ: 3EE853 =-------------------
> > ---= Windows Programmer in Rehab =---
> > -------------------------------------
> >
> > "If at first you don't succeed...
> > .. Skydiving is probbably not for you."
> >
> > On Thu, 14 Jun 2001, Shachar Shemesh wrote:
> >
> > > >
> > > >foreign DNS's keep his entry cached more than the said
> > > >"expire" (or is it "refresh"?) given 60 seconds, and when
> > he updates my
> > > >DNS, they don't update off me.
> > > >
> > > I have seen several cases of such behaviour, and not only with DNS.
> > >
> > > It seems that the various caches throughout the internet
> > don't like too
> > > short update times. The reason being the same reason such
> > caches were
> > > placed in the first place.
> > >
> > > An ISP places a cache to save on traffic. putting too low
> > an expire time
> > > spoils that.
> > >
> > > A value that should work OK, at least with some cases I've
> > heard of, is
> > > 180 (three minutes). It should still give your client a reasonably
> > > updating service.
> > >
> > > One good question is what happens if this is, indeed right?
> > Does it fill
> > > in it's default minimum?
> > >
> > > One more point - in some cases (noteably - Windows apps), a
> > single query
> > > is issued per app per domain per session, regardless of
> > timeout. I have
> > > seen it written somewhere, but I am not sure where (I think it was a
> > > reason against DNS load balancing).
> > >
> > > Shachar
> > >
> > >
> > >
> > >
> > > =================================================================
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> > >
> >
> >
> >
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> >
>
>
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