Internal DNS is very sluggish, and times out, If I change my DNS to use external DNS the performance is awesome for external sites, but I am unable to access internal sites. If I change my DNS back to the Internal DNS it slow back down and or times out.
Internal DNS is corp.company.com
External DNS is company.com
I not sure how to trouble shoot this?
I have recently upgraded from Server 2003 DNS to Server 2012 DNS...
Please advise on how to fix this type of situation?