"mmccaws2" <> wrote in message
news:2b875502-102e-454c-b8c4-...
> We're seeing intermittent problems and we're trying to eliminate DNS
> as possible source. For Windows server 2003 and 2008 I was told that
> the default cache when an address is resolve is set for 3 days. How
> does one check this?
>
> More info on the app. Since the app is for an externally connected
> site and it's was designed for us, I cannot give too much detail. But
> see if this is enough. It has an e commerce like front. Basically
> the user attaches to server A, user then purchases a license, then
> with the license number they can review it's status. So it looks
> like:
>
> From server A, a user connects and initiates a purchase
> - Server A then verifies credit card
> - once verified, server A attaches to another server, say Server B,
> that generates the license.
> - then user can retrieve license status form Server A.
>
> The problem results from connectivity loss between Server A and Server
> B. Server A is on an firewalled externally accessible network
> segment, and server B is internal.
>
> Why suspect DNS? I've noticed that when the internal DNS was changed
> over to new DNS that there were at least 3 names in the list of name
> servers that no longer exist. Could this present problems in
> resolving. And how might I be able to detect that?
>
> Thanks
>
> Mike
The TTL of a record is how long either the client-side resolver cache, or
the DNS server cache, will keep a record. I don't know where you got 3 days
from. It all depends on the record, and who created the record on their DNS
server.
How to check on the client?
ipconfig /displaydns
Look at each record, you can see the TTL displayed in seconds. Matter of
fact, if you hit arrow up and run it again, you will see it counting down.
For the server: Goto View, select Advanced. The cache folder pops up. Look
at what it has resolved. Right click on a record, and you will see it's TTL.
If you close it, and reopen the record, you can see it counting down each
time you open it.
Nameservers in the nameservers tab list what DNS servers are authorative for
YOUR zones, no one elses. So I can't see this being an issue at all.
I don;t think your problem is DNS, rather connectivity either due to the
firewall or your ISP. YOu didn't state whether the externally connected
ServerB is directly connected to the firewall, such as in your DMZ, or a 3rd
party company. If 3rd party company somewhere on the internet, then I would
look at connectivity between you and them. It could be your line is
saturated, their line is saturated, you are having ISP problems with the
line, etc. Too difficult to pinpoint.
If directly connected, I would look at connectivity through the firewall. If
the external domain name of the external server is the same name as the
internal domain name, then I would manually create a host record in DNS
under the zone and specifically provide the IP address of the external
ServerB. This way it is always the same and can eliminate any differences
with resolution. Difference can occur if the internal machines are using a
mixture of internal DNS servers (which they should ONLY be using) and
external DNS, which would give you different results, especially if the
names are the same.
So it depends on your scenario. I hope the explanation helps you pinpoint it
based on your scenerio.
--
Ace
This posting is provided "AS-IS" with no warranties or guarantees and
confers no rights.
Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCSA Messaging, MCT
Microsoft Certified Trainer
For urgent issues, you may want to contact Microsoft PSS directly. Please
check
http://support.microsoft.com for regional support phone numbers.
"Efficiency is doing things right; effectiveness is doing the right
things." - Peter F. Drucker
http://twitter.com/acefekay
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