[dns-operations] Unexpected behaviour from the B root servers?

[Joe Abley]

On 26-Feb-2007, at 14:49, Paul Vixie wrote:

>> Feb 26 09:59:50 Mail named[38107]: checkhints: view mail_recursive: \
>> 	b.root-servers.net/A (192.228.79.201) missing from hints
>> Feb 26 09:59:50 Mail named[38107]: checkhints: view mail_recursive: \
>> 	b.root-servers.net/A (128.9.0.107) extra record in hints
>
> if it's load balancing and/or anycast, then not every priming query  
> sent to
> "B" is going to be answered by the same server.  does anyone have a  
> tcpdump
> showing a response to a priming query that has this other address  
> for B?

I sent 500 queries for "HOSTNAME.BIND CH TXT" directly to  
192.228.79.201 using dig and listened for replies from a different  
address. The answers I got from the queries were all members of the  
set { "b1.isi.edu", "b2", "b3" } and I received no replies from  
anybody within 192.228.79.0/24 apart from 192.228.79.201. The query  
source in all cases was 199.212.90.21. (For what that's worth.)


Joe

[calamari:~]% date -u; \
 > ( n=500; while [ ${n} -gt 0 ]; do
subsh while> n=$((${n} - 1))
subsh while> dig @192.228.79.201 hostname.bind ch txt +short
subsh while> done; \
subsh> ) | awk '{ n++; r[$1]++; } END { for (i in r) { print i, r 
[i]; } }'; \
 > date -u
Mon Feb 26 21:10:39 GMT 2007
"b1.isi.edu" 75
"b2" 339
"b3" 86
Mon Feb 26 21:12:10 GMT 2007
[calamari:~]%

[calamari:~]% sudo tcpdump -i en0 -v -v -s 0 -n net 192.228.79.0/24  
and not host 192.228.79.201
tcpdump: listening on en0, link-type EN10MB (Ethernet), capture size  
65535 bytes
^C
0 packets captured
8184 packets received by filter
0 packets dropped by kernel
[calamari:~]%

[calamari:~]% traceroute 192.228.79.201
traceroute to 192.228.79.201 (192.228.79.201), 64 hops max, 40 byte  
packets
1  yxu1b (199.212.90.3)  1.653 ms  1.111 ms  1.142 ms
2  206.248.154.102 (206.248.154.102)  48.331 ms  48.347 ms  50.468 ms
3  65.39.134.1 (65.39.134.1)  47.933 ms  47.865 ms  49.540 ms
4  65.39.198.250 (65.39.198.250)  51.965 ms  52.810 ms  49.428 ms
5  oc48pos7-0.tor-1yg-cor-1.peer1.net (216.187.114.161)  49.837 ms   
51.995 ms  52.850 ms
6  oc48pos0-0.chi-dis-1.peer1.net (216.187.114.141)  62.629 ms   
65.179 ms  63.865 ms
7  ber2-ge-8-3.chicagoequinix.savvis.net (208.174.225.229)  57.707  
ms  57.826 ms  58.272 ms
8  bpr1-ge-7-1-0.chicagoequinix.savvis.net (208.175.9.134)  58.997  
ms  59.488 ms  62.801 ms
9  sl-st21-chi15-3.sprintlink.net (208.174.226.66)  57.552 ms  58.725  
ms  58.621 ms
10  sl-bb22-chi-2-0.sprintlink.net (144.232.20.20)  60.256 ms  58.919  
ms  59.624 ms
11  sl-bb21-kc-3-0.sprintlink.net (144.232.20.129)  70.351 ms  70.934  
ms  70.397 ms
12  sl-bb20-kc-15-0.sprintlink.net (144.232.2.117)  70.898 ms  70.618  
ms  70.534 ms
13  sl-bb25-fw-13-0.sprintlink.net (144.232.20.4)  80.599 ms  81.520  
ms  80.521 ms
14  sl-bb21-ana-12-0-0.sprintlink.net (144.232.20.64)  109.349 ms   
109.591 ms  111.138 ms
15  sl-bb23-ana-13-0.sprintlink.net (144.232.1.186)  106.457 ms   
107.928 ms  108.129 ms
16  sl-gw22-ana-10-0.sprintlink.net (144.232.1.106)  114.825 ms   
108.120 ms  108.518 ms
17  sl-veriz6-1-0.sprintlink.net (144.223.30.134)  112.857 ms   
113.247 ms  119.458 ms
18  198.32.16.22 (198.32.16.22)  124.369 ms  121.810 ms  120.067 ms
19  192.228.79.8 (192.228.79.8)  120.461 ms  126.496 ms  131.482 ms
[calamari:~]%