cache server

[sally wong]

Hi,

I have posted here before regarding a caching server.

I have this caching server set up. Our company
maintains the primary and caching server. UUNET
maintains the slave server.

My understanding of the caching server is that if
caching server does not have the info, it will ask the
primary server or other server outside on the
internet, is this correct?

I have noticed that our caching server does not always
notice the new DNS entries immediately. It sometimes
picks up the entry immediately but sometimes not.
Sometime I have to wait some hours for the new entries
to be picked up by the caching server.

Usually how long will it take the entry to take its
way to caching server? It seems to me that eventually
the caching server picks up the new entries. I do not
know how long it take, and where on the primary server
controls such variable?

I have checked the IPs of our slave name servers, they
are the correct IP.

Can someone help me with this?

Many thanks

[Brad Knowles]

At 3:11 PM -0700 7/12/01, sally wong wrote:

> My understanding of the caching server is that if
> caching server does not have the info, it will ask the
> primary server or other server outside on the
> internet, is this correct?

Depending on how it is set up (whether it uses forwarding or
not), a caching server will try to go find the answer on the
Internet, if it does not have the answer in its local cache. That's
the entire idea.

> I have noticed that our caching server does not always
> notice the new DNS entries immediately. It sometimes
> picks up the entry immediately but sometimes not.
> Sometime I have to wait some hours for the new entries
> to be picked up by the caching server.

Not surprising. You've got old records that are cached, and
therefore the caching server has no reason to try to go update them
-- until they records time out.

> Usually how long will it take the entry to take its
> way to caching server? It seems to me that eventually
> the caching server picks up the new entries. I do not
> know how long it take, and where on the primary server
> controls such variable?

On average, it will take have the TTL of the changed record
before the majority of servers detect the change. If you want to
propagate changes faster than this, you need to decrease your TTL to
match.

--
Brad Knowles, <brad.k...@skynet.be>

/* efdtt.c Author: Charles M. Hannum <ro...@ihack.net> */
/* Represented as 1045 digit prime number by Phil Carmody */
/* Prime as DNS cname chain by Roy Arends and Walter Belgers */
/* */
/* Usage is: cat title-key scrambled.vob | efdtt >clear.vob */
/* where title-key = "153 2 8 105 225" or other similar 5-byte key */

dig decss.friet.org|perl -ne'if(/^x/){s/[x.]//g;print pack(H124,$_)}'