[PLUG] DNS Problems

[Ed Sawicki]

The quality of big-ISP DNS-related services is eroding.
I do quite a bit of consulting in the area of DNS and
I've noticed slowdowns in two areas:

1.Getting non-authoritative answers from big-ISP DNS
  servers/caches seems to be getting slower. I first
  noticed this problem when a customer complained about
  his Windows computers not being able to get to Web
  sites. Internet Explorer would fail with an error.

  The Windows computers were pointing to his ISPs DNS
  servers. A trace of the packets revealed that the
  servers frequently took more than two to four seconds
  to respond - even if the name had been resolved in the
  recent past. A temporary solution was to patch the
  Registry to make Windows more tolerant of delays.

  The solution was to stop using his ISP's DNS servers.
  He was then getting many or most answers in less than
  20 milliseconds.

2.Big-ISP DNS servers often take hours to do a zone transfer
  once notified. I've been monitoring this closely for my
  customers who host their DNS here. Four hour delays are
  not unusual. For customers who consider this a problem,
  the solution is to stop using the ISP's DNS servers.

Using big-ISP DNS services always seems to be a problem in
one way or another.

Ed

On Fri, 2003-08-01 at 21:19, Robbert van Andel wrote:
> Has anyone on the list using Comcast.net noticed any slow downs with
> resolving domains recently? The last couple of days sites that I don't
> go to on a regular basis seem to take an extraordinary amount of time to
> resolve.  Is there anything I can do to speed up the resolution?  Right
> now I run RedHat 8.  The Network Configuration gui shows nothing under
> DNS, under devices I have eth0 active and the properties of that shows a
> checked checkbox next to Automatically obtain DNS information from
> provider.
> 
> Any help would be appreciated.
> Robbert van Andel
-- 
Ed Sawicki <ed at alcpress.com>
ALC