Having worked for a largish technical support organization, one thing I do
know....
... sometimes answers are given because they make the problem go away, not
because the answer is correct.
Whoever told you about ISPs downloading the root from NSI, or ICANN or
someone found one of those "make the angry customer go away" answers.
Everyone who does DNS should own a copy of DNS and BIND. Even if you
aren't using BIND, most name servers work alike.
At the top of each DNS zone is an SOA record, and it contains several
numbers. Here is one of mine:
@ IN SOA ns.BusComNet.com. sysadmin.BusComNet.com. (
2002052701 ; s/n
28800 ; refresh: 8 hours
3600 ; retry: 1 hour
604800 ; expire: 7 days
432000 ; TTL: 5 days
)
The text after the semicolons are comments. Saves me pulling out the book.
The key number here is TTL -- this tells another DNS server how long they
can keep information cached.
If you visit a site with this zone file (shameless plug:
http://www.islandshirts.com) your local name server will get the IP
(64.241.70.67) and it may keep it for up to 5 days.
If I make a change 10 seconds after your ISP queries DNS, you won't see
that change until sometime on Thursday -- and if you keep checking every 15
minutes, you'll make sure that they cache the old, bad data because your
ISPs' name server thinks the site must be popular.
I'm reshuffling addresses a little bit, so I've been setting the TTL on
those zones down to something very short -- but I have to wait the full
five days (at least) to allow my old info to expire from everyone else's
cache -- and even then some caches don't expire on time.
As an aside, if a customer tells me they're leaving, we set their TTL short
so that the transition goes quickly and smoothly. If they don't tell,
well, things are going to be a little odd for the next five days. Higher
TTL means other DNS servers are likely to cache things here longer, lower
TTL means we can make changes and the bad news will dissappear more
quickly. It's a trade off.
-- Lynn
-----Original Message-----
From: POWERHOUSE [SMTP:[EMAIL PROTECTED]]
Sent: Saturday, June 22, 2002 6:30 PM
To: William X Walsh
Cc: Dave Warren; Charles Edmunds; [EMAIL PROTECTED]
Subject: Re: Nameserver Questions
More like UPDATING the database, that would answer the question as to WHY
some ISP's can see a new nameserver within 24 hours, and others cannot for
up to 3 or 4 days.
If it's not done that way, then there is another big mystery as to why it
would not work, with all
ISP's like they do with the bigger ones.
Case and point:
about 8 months ago, we had a VERY "Technically Challenged" customer, who we
basically had
to do EVERYTHING for, including change the nameservers. Ok, all done. Two
days later, he
calls us, and when I take the call, he starts yelling about his domain was
NOT working, that he should
have never switched companies, and blah, blah, blah.
He said he gets a Page Not Found.
So I open my browser up, and it loads just like normal, our Standard
"Coming
Soon" page that gets created
when the Site is created.
So I talk him into waiting for 24 hours more. about that much time passes,
and I'm told he is on the phone again.
So I walk him through Clearing his Cache, and lots of other things, and
STILL he's getting Page Not Found.
This is after 3 days since We did everything. I had him go to another site,
that he's more then likely never visited
and it loaded. Ok. So what's the problem? It loads for me, but NOT for him.
His Page Not Found says cannot locate DNS, at the bottom.
I TOLD him that what is more then likely happening, is that his ISP has NOT
updated their Database, to point
his browser to the correct server. He said, Oh, ok. He called them. The
next
day he called back, and said that
it was still NOT WORKING, and his ISP said that it could take up to 96
hours
for them to be "PROPAGATED"
or pointing to the NEW nameservers.
So, the next day, bang, it worked fine.
So if the Different ISP's do NOT just update their database, Why does this
happen all the time?
Do we have yet another mystery, like the Bermuda Triangle? Stuff just
happens, with NO explanation?
What is happening so that I do NOT lie to another customer, although be it
not on purpose?
I do NOT like NOT knowing the truth.
If anyone out there knows FIRST HAND, not HEARSAY, please respond. All of
us, do NOT know for sure,
we are more then likely repeating what we have been TOLD. What is the
LOGICAL explanation?
All I know for a FACT, is that when I worked at AOL, I was told just what I
said, and that is what to say
to customers who call, and say they can't get their website to work, we had
to ask if they had just made a change
to their nameserver, that way we did not spend a bunch of time poking
through the pc, seeing if our software
had a problem.
Thank you.
Richard
----- Original Message -----
From: "wxWeb.com" <[EMAIL PROTECTED]>
To: "POWERHOUSE" <[EMAIL PROTECTED]>
Cc: "Dave Warren" <[EMAIL PROTECTED]>; "Charles Edmunds"
<[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Saturday, June 22, 2002 8:04 PM
Subject: Re: Nameserver Questions
> Saturday, June 22, 2002, 12:06:24 PM, POWERHOUSE wrote:
>
> > Actually I USED to work for AOL, I know for a FACT That some of the
Smaller
> > ISP's USED TO only
> > download the master Database from ICANN only 1 time PER WEEK.
>
> Why would a small ISP download anything?
>
> That isn't how the DNS works.
>
> --
> Best regards,
> William X Walsh <[EMAIL PROTECTED]>
> --
> OpenSRS installation and customizations
> Payment Processing Integration
> Apache Installation and Support Services
> http://www.wxsoft.com/
>
>
>
>
