DSN resolution strange behavior.

Hi Experts,

I have an issue at a new client that is causing their LOB app to fail. It happens intermittently and can be temporarily resolved by a client restart but will occur again after a few minutes and the LOB app will crash. The issue is that when pinging the SQL server by name the ping reply is from Obviously this is a loopback address and non-workable. Any suggestions that could be causing this? As a temporary fix I have added the SQL server address and IP to the hosts file on each client, but this is not a long term workable solution. The SQL server has a manually assigned IP address and all the DNS information is entered correctly on the DNS server.
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Chris HInfrastructure ManagerCommented:
Check to make sure the user doesn't have an AV with internet security that is using a "Secure" DNS function.  I had this issue with AVAST and it using OPEN DNS after the Internet security module loaded (loads like a minute after everything else).  My internet exchange server and web server were resolving publicly.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Paul MacDonaldDirector, Information SystemsCommented:
I'm hoping the SQL server isn't using DHCP, but that may be worth confirming as well.
Dougj182Author Commented:
@ choward16980: I believe the customer is using a Kaspersky endpoint AV solution. Do you know if this has a "Secure" DNS function? If only started happening last week, they have never had issues before then.
Discover the Answer to Productive IT

Discover app within WatchGuard's Wi-Fi Cloud helps you optimize W-Fi user experience with the most complete set of visibility, troubleshooting, and network health features. Quickly pinpointing network problems will lead to more happy users and most importantly, productive IT.

Dougj182Author Commented:
@ paulmacd: Please see the final sentence of the OP.
Chris HInfrastructure ManagerCommented:
I want to say Kaspersky was the first, since conficker....

Uninstall the AV and test.  Don't disable, uninstall.
Dougj182Author Commented:
Thanks, I'll return and report but it may be a couple of days till I can get out to the customer next.

If it's has had the "feature" for so long, any idea why would it only start effecting the system a week ago?
Chris HInfrastructure ManagerCommented:
Someone may have added a conflicting public address.  My case, my exchange server had the same hostname inside and outside.  Try typing in ping sqlservername.domainname.com and see what ip address it is actively pinging.
DrDave242Senior Support EngineerCommented:
Are the client machines configured to use the correct DNS server(s)? If you use nslookup to query the internal DNS server for the name of the SQL server, what gets returned?
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.