Im using Peplink Balance 720 . My PC DNS address pointing to Peplink LAN IP . Its deployed in NAT Mode. I have two WAN Link . WAN 1 is pointing locally in Malaysia and WAN 2 pointing to Singapore as gateway out. There is reason why we have such WAN requirement.
I have Outbound Policy to facebook.com to route via WAN 1 , which is resolve the domain using WAN 1 Interface DNS address which reside in Malaysia too. These give good ping response time since facebook hosted locally in malaysia . In another word, Malaysia ISP DNS, resolve locally hosted facebook IP address which give better ping responce-time if use LOCAL ISP wan link.
I have another Oubound Policy for Youtube.com to route via WAN 2, since Singapore youtube gives better ping response time on my WAN 2 < 10ms . I have set WAN 2 interface to use Singapore ISP DNS . But whenever i do nslookup in my PC, its resolve youtube.com using WAN 1 Interface DNS, and not WAN 2 interface DNS( as its suppose to) and then it route the traffic via WAN 2. This makes the domain resolve to malaysia IP and then routed to Singapore(following my outbound policy) , and then routed back again to Malaysia via ISP backbone which end up in high latency.