In current DNS handling, NetScaler Gateway plugin sends a “GET/DNS” request for DNS (or WINS) lookup. When NetScaler receives such a request, it creates an actual DNS packet and sends it to the DNS server configured on NetScaler.
When NetScaler receives the response from the DNS server, it sends a resolved IP to NetScaler Gateway plugin and plugin in turn will send this to the requested application. Therefore, whenever there is a DNS lookup, because of the preceding design you will receive only one IP.
NetScaler provides two nsapimgr knobs (mentioned in additional resources section) for controlling this behavior. If you configure these knobs on NetScaler, NetScaler Gateway plugin sends DNS query packets transparently to configured DNS server and DNS response is also received transparently.