Limiting the number of clientsBIND 9 gives you the ability to restrict the number of clients your name server will serve concurrently. You can apply a limit to the number of recursive clients (resolvers plus name servers using your name server as a forwarder) with the recursive-clients substatement:
options {
recursive-clients 10;
};
The default limit is 1000. If you find your name server refusing recursive queries and logging, as shown by an error message like this one:
Sep 22 02:26:11 terminator named[13979]: client 192.249.249.151#1677: no more
recursive clients: quota reached
you may want to increase the limit. Conversely, if you find your name server struggling to keep up with the deluge of recursive queries it receives, you could lower the limit.
You can also apply a limit to the number of concurrent TCP connections your name server will process (for zone transfers and TCP-based queries) with the tcp-clients substatement. TCP connections consume considerably more resources than UDP because the host needs to track the state of the TCP connection. The default limit is 100.

...................
Nov 27 13:17:58 dns named[1966]: zone localhost.zone/IN: has no NS records
Nov 27 13:17:58 dns named[1966]: zone named.local/IN: has no NS records
Nov 27 13:17:58 dns named[1966]: zone hk.hn/IN: has no NS records
...................

解决方法：
原因为直接copy web上的配置文件，配置文件中的NS行没有空格或tab，添加上一个tab就可以了。
如"IN NS localhost".换成" IN NS localhost."即可。

*********************************************************************************
xxx.com. IN MX 10 mx01.xxx.com.
xxx.com. IN MX 20 mx02.xxx.com.
xxx.com. IN TXT "v=spf1 ip4:61.211.120.156 a:xxx.com mx:xxx.com -all"
mx01.xxx.com. IN A 61.211.120.156
mx02.xxx.com. IN A 61.211.120.157
sysmail.xxx.com. IN MX 10 mx03.xxx.com
mx03.xxx.com. IN A 61.211.120.158
sysmail.xxx.com. IN TXT "v=spf1 ip4:61.211.120.158 a:sysmail.xxx.com mx:sysmail.xxx.com -all"
*********************************************************************************

1、dig -t mx sysmail.dianping.com
2、 nslookup
set q=mx
sysmail.xxx.com

1:dig -t txt sysmail.xxx.com
2: nslookup
set q=txt
sysmail.xxx.com

192.168.100.1
192.168.100.2

abc.com. IN MX 10 mx01.abc.com.
abc.com. IN TXT "v=spf1 ip4:192.168.100.1 a:abc.com mx:abc.com -all"
mx01.abc.com. IN A 192.168.100.1
pop3.abc.com. IN A 192.168.100.1
smtp.abc.com. IN A 192.168.100.1
smtp.abc.com. IN A 192.168.100.2

// Default named.conf generated by install of bind-9.2.4-28.el4
options {
    directory "/var/named";
    pid-file "/var/run/named/named.pid";
    dump-file "/var/named/data/cache_dump.db";
    statistics-file "/var/named/data/named_stats.txt";
    Allow-transfer {tran;};
};

acl tran {192.168.0.174;};

zone "localhost" IN {
    type master;
    file "localhost.zone";
    allow-update { none; };
};

zone "0.0.127.in-addr.arpa" IN {
    type master;
    file "named.local";
    allow-update { none; };
};

zone"hk.hn"{
    type master;
    file "hk.hn";
    allow-transfer {192.168.100.174;};
};

include "/etc/rndc.key";

$TTL 86400
$ORIGIN localhost.
@ 1D IN SOA @ root (
    42 ; serial (d. adams)
    3H ; refresh
    15M ; retry
    1W ; expiry
1D ) ; minimum
1D IN NS @
1D IN A 127.0.0.1

$TTL 86400
@ IN SOA localhost. root.localhost. (
    2008063017 ; Serial
    28800 ; Refresh
    14400 ; Retry
    3600000 ; Expire
    86400 ) ; Minimum
IN NS localhost.
1 IN PTR localhost.

$TTL 1m
@ IN SOA ns1.localhost.cn root.ns1.localhost.cn. (
    2008063017 ; Serial
    108 ; Refresh
    360 ; Retry
    3600 ; Expire
    360 ) ; Minimum
IN NS localhost.
IN NS ns1
MX 5 mx

test1 IN A 192.168.100.1
test2 IN A 192.168.100.2

http://www.webreference.com/cgi-bin/nslookup.cgi
http://www.bankes.com/nslookup.htm
http://network-tools.com/nslook/
http://www.kloth.net/services/nslookup.php
http://dns411.com/
http://www.zoneedit.com/lookup.html
http://centralops.net/co/NsLookup.vbs.asp
http://www.channel1.com/cgi-bin/nslookup.cgi
http://www.subnetonline.com/cgi-bin/webtools/nslookup.pl
http://networking.ringofsaturn.com/Tools/nslookup.php
http://www.webmaster-toolkit.com/ns-lookup.shtml
http://www.simplelogic.com/net_utils/NsLookup.asp
http://helpy.com.ar/NSLookup.php
http://helios.ccunix.ccu.edu.tw/cgi-bin/nslookup.cgi
http://www.tellurian.com/scripts/tools/nslookup.asp
http://www.tti.co.jp/nslookup/i/
http://www.nsg.northwestern.edu/cgi-bin/nslookup.cgi
http://www.his.com/cgi-bin/nslookup
http://www.enc.com.au/itools/nslookup.php

acl CNCGROUP {
58.16.0.0/16;
58.17.0.0/17;
58.17.128.0/17;
58.18.0.0/16;
58.19.0.0/16;
............................
58.20.0.0/16;
58.21.0.0/16;
58.22.0.0/15;
58.144.0.0/16;
222.163.64.0/18;
222.163.128.0/17;
};
view "CNCGROUP" {//定义网通域文件
      match-clients{CNCGROUP;};
      recursion yes;
      zone "sian.com.cn"{
           type master;
           file "CNC_sian.com.cn";
      };
};

view "external" {//定义非网通域文件
      match-clients { any; };
      recursion no;
      zone "sian.com.cn"{
           type master;
           file "sian.com.cn";
      };
};