Response Times on Different Virtual Interfaces

[Jiann-Ming Su]

I'm running BIND 9.6.1_P1.  The server has multiple virtual interfaces that BIND 
listens on:

listen-on { 127.0.0.1; 172.30.0.213; 192.168.43.98; };

Sometimes I can get quite a huge difference in response time depending on which 
virtual interface I query against.  For example, most of our users use 
172.30.0.213.  When queries against it becomes slow, I can query against the 
192.168.43.98 address and get reasonable response times.  Is this a limitation 
of BIND, the version of BIND I'm running, or a misconfiguration on my part? 
 Thanks for any tips or insights.