check domain controller

I have an app that I maintain that authenticates off AD. Problem is if a
domain controller goes down the app does not failover. I need a way to
say
Check this: LDAP://domainController1/DC=xxx,DC=xxx,DC=xxx
If this does not work go here:
LDAP://domainController2/DC=xxx,DC=xxx,DC=xxx

I'm not sure how to do that.

Bob Wakefield
"Don't be so concerned with living that you forget to live"
913.905.5112

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