ongoing issues.

Re: ongoing issues.

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At 8:57 AM -0400 4/14/00, Adam West wrote:
>I think I am having a similar problems with sporadic A record responses. I
>have two separate DNS servers (ns1.knowledgeexpress.com a 7600 and
>ns2.knowledgeexpress.com a 6100). I had multiple secondary IP's, but removed
>them as I have been working on troubleshooting the problem. I used my DNS
>Expert to test all the records and have only warnings (not errors) about
>duplicate www records. I have www.knowldgeexpress.com pointed to two IP
>addresses. The manual show that this was OK to do if you want a round robin.
>I am starting to think that is the problem, i.e.-it isn't resolving fast
>enough. On the other hand, it seems to be sporadic, like the report below.
>I am also out of ideas...

Aside from misspelling your domain (you left out an "e"), I can't
find where you've made any errors.

These records should not cause DNS Expert to claim you have duplicate
A records:
www.knowledgeexpress.com. A 209.49.229.30
www.knowledgeexpress.com. A 209.49.229.31

After all, they're not duplicates; they differ in the address.

One reason for occasional reports that your domain can't be found is
resolver speed - the potential visitor's resolver doesn't get a
response back to the web browser fast enough. Some operating systems
have a timeout period of 7 seconds. In that time, the resolver has to
locate the root servers, ask a root server, ask your servers,
evaluate the answer, and respond to the client.

If the resolver isn't fast enough, this can cause a sporadic "name
doesn't exist" error. However, the resolver will continue resolving
the name, even after the time limit has been exceeded. If the client
tries again while the browser has the name in cache, the name will
already be known and an answer will be given back immediately.

Reasons the resolver might not find the name in time:

o Most resolvers try to keep track of which root server responds most
quickly. This can change at a moment's notice, though. If it does,
the root server may not respond for several seconds, if at all. The
resolver _should_ try all the rest within a second or two.

o The resolver might simply be slow, due to hardware, operating
system, current load, or a combination of these.

o The resolver's connection to the Internet might be slow, due to
excessive traffic, a slow line, or a combination of these factors.

o The DNS servers queried for the name might respond slowly. This may
be because of net traffic on the server's end, current load, a
generally slow server, etc.

o The resolver might run across a lame delegation for the domain.
This in turn might cause it to have to backtrack and pick another
server.

All of these factors can slow things down enough to exceed the time
limit. As a domain owner, you can really only control a few of these
factors. It is to your benefit to have your domain hosted on a
relatively large number of servers (more than 2), each of which is
connected to the net in a different place, via a different provider.
It is also of benefit to have your ISP (or your ISP's bandwidth
provider) host your domain.
____________________________________________________________________
Chris Buxton cbuxton@menandmice.com
Men & Mice http://www.menandmice.com
Makers of: QuickDNS Pro

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