Resolve domain in two ethernet

I have two ethernet for two connection in WinSvr2012 as Exchange Server 2013 SP1, one to local network with primary DNS in local dns server.other to IP public with primary DNS is provider dns server. when i need to lookup a domain,it's reference to local dns server, so its domain cannot resolve,but when i use nslookup and change server to public dns server, the domain is resolve.

any advice?

Regards, Noval