[CentOS] named log entries - Are any of these a problem?

Wed Oct 8 13:05:38 UTC 2014
Bill Gee <bgee at campercaver.net>

Hello everyone -

I run bind version 9.8.2 on CentOS 6.5.  The daily logwatch run sends me the 
following items.  Are any of these a real problem?

============  
checkhints: extra NS 'A.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'B.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'C.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'D.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'E.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'F.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'G.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'H.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'I.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'J.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'K.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'L.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: extra NS 'M.ROOT-SERVERS.NET' in hints: 170 Time(s)
    checkhints: unable to find root NS 'ns1.dnslibre.info' in hints: 147 
Time(s)
    checkhints: unable to find root NS 'ns1.opennic.glue' in hints: 170 Time(s)
    checkhints: unable to find root NS 'ns10.opennic.glue' in hints: 170 
Time(s)
    checkhints: unable to find root NS 'ns2.dnslibre.info' in hints: 147 
Time(s)
    checkhints: unable to find root NS 'ns2.opennic.glue' in hints: 170 Time(s)
    checkhints: unable to find root NS 'ns3.opennic.glue' in hints: 170 Time(s)
    checkhints: unable to find root NS 'ns4.opennic.glue' in hints: 170 Time(s)
    checkhints: unable to find root NS 'ns5.opennic.glue' in hints: 170 Time(s)
    checkhints: unable to find root NS 'ns6.opennic.glue' in hints: 170 Time(s)
    checkhints: unable to find root NS 'ns7.opennic.glue' in hints: 170 Time(s)
    checkhints: unable to find root NS 'ns8.opennic.glue' in hints: 170 Time(s)
    checkhints: unable to find root NS 'ns9.opennic.glue' in hints: 147 Time(s)
    clients-per-query decreased to 10: 2 Time(s)
(repeated many time with various numbers)
===================

The hints file DOES contain two entries for each of the ROOT-SERVERS.  One is 
the ipv4 address and the other is the ipv6 address.  I use the hints file 
downloaded from http://www.internic.net/domain/named.root .

The hints file does NOT contain any entries for the opennic.glue or 
dnslibre.info servers.  However, when I run "rndc -all", the output shows that 
bind has entries for those servers.  The names will resolve and answer ping.

I searched all over trying to find information on the clients-per-query 
setting.  My named.conf file does not contain an entry for clients-per-query.  
Is there some detailed documentation on this setting?  What does it really do?

Three more notes:  1) I see no problems in daily operation.  All web browsing 
works as does resolution for local machines.  2) This bind server does not get 
queries from outside my local network.  3) I use OpenNIC as the "forwarders" 
servers.  I used to use OpenDNS until they stopped handling Yahoo email 
correctly.

Thanks - Bill Gee