NSCD is not caching the negative result of DNS query in Red Hat Enterprise Linux 6.6

Issue

• We have several machines where httpd is running.
• And, nscd is used to cache the DNS query.
• One machine only has a low cache hit rate (1%) for hosts.
• In a not-working machine:

# nscd -g
... snip ...
hosts cache:
... snip ...
          72296  cache hits on positive entries
              6  cache hits on negative entries
          89820  cache misses on positive entries
        5828692  cache misses on negative entries
              1% cache hit rate

• What is the root cause of this?