BIND non-cached resolution taking 2-4 seconds each time
ee99ee at gmail.com
ee99ee at gmail.com
Sat Sep 16 14:43:50 UTC 2006
I'm having a problem with BIND 9 taking FOREVER to resolve DNS
requests. Both are fresh installs of CentOS on PIII hardware. Both are
in a well connected network (2 full DS-3's that aren't very used from
two providers; we do our own BGP).
Here is my named.conf:
------------------------------------
acl recurseallow {
208.67.56.0/22;
127.0.0.1;
};
acl trusted {
};
options {
directory "/var/named";
allow-transfer { trusted; };
allow-recursion { recurseallow; };
query-source port 53;
};
include "/etc/rndc.key";
zone "." {
type hint;
file "named.root";
};
------------------------------------
Here is my root hints file:
------------------------------------
. 6D IN NS A.ROOT-SERVERS.NET.
. 6D IN NS B.ROOT-SERVERS.NET.
. 6D IN NS C.ROOT-SERVERS.NET.
. 6D IN NS D.ROOT-SERVERS.NET.
. 6D IN NS E.ROOT-SERVERS.NET.
. 6D IN NS F.ROOT-SERVERS.NET.
. 6D IN NS G.ROOT-SERVERS.NET.
. 6D IN NS H.ROOT-SERVERS.NET.
. 6D IN NS I.ROOT-SERVERS.NET.
. 6D IN NS J.ROOT-SERVERS.NET.
. 6D IN NS K.ROOT-SERVERS.NET.
. 6D IN NS L.ROOT-SERVERS.NET.
. 6D IN NS M.ROOT-SERVERS.NET.
A.ROOT-SERVERS.NET. 6D IN A 198.41.0.4
B.ROOT-SERVERS.NET. 6D IN A 128.9.0.107
C.ROOT-SERVERS.NET. 6D IN A 192.33.4.12
D.ROOT-SERVERS.NET. 6D IN A 128.8.10.90
E.ROOT-SERVERS.NET. 6D IN A 192.203.230.10
F.ROOT-SERVERS.NET. 6D IN A 192.5.5.241
G.ROOT-SERVERS.NET. 6D IN A 192.112.36.4
H.ROOT-SERVERS.NET. 6D IN A 128.63.2.53
I.ROOT-SERVERS.NET. 6D IN A 192.36.148.17
J.ROOT-SERVERS.NET. 6D IN A 198.41.0.10
K.ROOT-SERVERS.NET. 6D IN A 193.0.14.129
L.ROOT-SERVERS.NET. 6D IN A 198.32.64.12
M.ROOT-SERVERS.NET. 6D IN A 202.12.27.33
------------------------------------
Here is the output of TCP dump doing a sample query after running "rndc
flush" then "dig @localhost theplanet.com"
------------------------------------
08:50:04.249815 IP 208.67.56.6.domain > 193.0.14.129.domain: 11509%
[1au] A? theplanet.com. (42)
08:50:04.251185 IP 208.67.56.6.domain > 193.0.14.129.domain: 6690%
[1au] NS? . (28)
08:50:04.393408 IP 193.0.14.129.domain > 208.67.56.6.domain: 11509-
0/13/16 (530)
08:50:04.394688 IP 193.0.14.129.domain > 208.67.56.6.domain: 6690*-
13/0/14 NS a.root-servers.net.,[|domain]
08:50:06.397444 IP 208.67.56.6.domain > 192.55.83.30.domain: 13032%
[1au] A? theplanet.com. (42)
08:50:06.651124 IP 192.55.83.30.domain > 208.67.56.6.domain: 13032
FormErr- [0q] 0/0/0 (12)
08:50:06.651819 IP 208.67.56.6.domain > 192.55.83.30.domain: 3266 A?
theplanet.com. (31)
08:50:06.909213 IP 192.55.83.30.domain > 208.67.56.6.domain: 3266-
0/2/12 (259)
08:50:06.910512 IP 208.67.56.6.domain > 207.44.128.230.domain: 17183%
[1au] A? theplanet.com. (42)
08:50:06.956252 IP 207.44.128.230.domain > 208.67.56.6.domain: 17183*-
1/2/13 A 70.87.6.11 (286)
------------------------------------
Notice the 2 second delay between lines 4 and 5? The result took 2.5
seconds for dig to respond. Once it's cached, it takes only a few ms to
get the same thing back, it's just that first time query that takes
FOREVER.
In an effort to be through, more information is below.
My /etc/hosts:
------------------------------------
127.0.0.1 localhost.localdomain localhost
------------------------------------
My /etc/host.conf:
------------------------------------
order hosts,bind
------------------------------------
Output of some commands:
------------------------------------
[~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
208.67.56.0 0.0.0.0 255.255.255.224 U 0 0 0
eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0
eth0
0.0.0.0 208.67.56.3 0.0.0.0 UG 0 0 0
eth0
[~]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:01:29:20:9A:A3
inet addr:208.67.56.6 Bcast:208.67.56.31
Mask:255.255.255.224
inet6 addr: fe80::201:29ff:fe20:9aa3/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1604748 errors:0 dropped:0 overruns:0 frame:0
TX packets:1088829 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:193923454 (184.9 MiB) TX bytes:145317266 (138.5
MiB)
Interrupt:11 Base address:0xec00
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:2605 errors:0 dropped:0 overruns:0 frame:0
TX packets:2605 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:4311177 (4.1 MiB) TX bytes:4311177 (4.1 MiB)
[~]#
------------------------------------
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