Occasional problems resolving from capitalone.com

[Rich Goodson]

Hi all,

I have some caching resolvers that are running BIND 9.4.3.  They  
answer about 30k-ish recursive queries per second at peak hours.

Every couple of weeks or so, we get calls to customer support with  
complaints that the www.capitalone.com web site is unavailable.
The CNAME for www.capitalone.com points to www.wpex.capitalone.com,  
which is served out by a different set of name servers:
wpex.capitalone.com.	3600	IN	NS	ns2-mockingbird.wpex.capitalone.com.
wpex.capitalone.com.	3600	IN	NS	ns1-cardinal.wpex.capitalone.com.
those name servers are, apparently, occasionally unavailable, at least  
from our network, and we end up with a negative cached record that I  
suspect lasts 48 hours.

right now, I am doing a workaround with a shell script that looks  
something like this (this is just a snippet, btw, not the full script):
rndc dumpdb
if [ `grep capitalone.com /var/dump/named_dump.db | grep -q  
NXDOMAIN` ]; then
	rndc flushname `grep capitalone.com | grep NXDOMAIN | awk '{print $1}'`

This may not be the only host/domain that we have occasional  
difficulty with, but it's certainly the only one that has calls from  
CS that get filtered down to me.  Is this something broken in our  
resolvers, or is this (as I suspect) just a really wonky and somewhat  
broken implementation on the part of capitalone.com?  Is anyone else  
having difficulty with resolution of this domain?

Here's a dig from one of our name servers. (the dig is from my  
workstation which has 9.4.2-P2 on it).

; <<>> DiG 9.4.2-P2 <<>> +trace @wdmdc-dns1 www.capitalone.com
; (1 server found)
;; global options:  printcmd
.			242071	IN	NS	K.ROOT-SERVERS.NET.
.			242071	IN	NS	H.ROOT-SERVERS.NET.
.			242071	IN	NS	J.ROOT-SERVERS.NET.
.			242071	IN	NS	L.ROOT-SERVERS.NET.
.			242071	IN	NS	B.ROOT-SERVERS.NET.
.			242071	IN	NS	D.ROOT-SERVERS.NET.
.			242071	IN	NS	M.ROOT-SERVERS.NET.
.			242071	IN	NS	I.ROOT-SERVERS.NET.
.			242071	IN	NS	E.ROOT-SERVERS.NET.
.			242071	IN	NS	F.ROOT-SERVERS.NET.
.			242071	IN	NS	A.ROOT-SERVERS.NET.
.			242071	IN	NS	C.ROOT-SERVERS.NET.
.			242071	IN	NS	G.ROOT-SERVERS.NET.
;; Received 512 bytes from 12.207.232.47#53(12.207.232.47) in 17 ms

com.			172800	IN	NS	K.GTLD-SERVERS.NET.
com.			172800	IN	NS	C.GTLD-SERVERS.NET.
com.			172800	IN	NS	A.GTLD-SERVERS.NET.
com.			172800	IN	NS	M.GTLD-SERVERS.NET.
com.			172800	IN	NS	L.GTLD-SERVERS.NET.
com.			172800	IN	NS	J.GTLD-SERVERS.NET.
com.			172800	IN	NS	D.GTLD-SERVERS.NET.
com.			172800	IN	NS	I.GTLD-SERVERS.NET.
com.			172800	IN	NS	F.GTLD-SERVERS.NET.
com.			172800	IN	NS	G.GTLD-SERVERS.NET.
com.			172800	IN	NS	B.GTLD-SERVERS.NET.
com.			172800	IN	NS	E.GTLD-SERVERS.NET.
com.			172800	IN	NS	H.GTLD-SERVERS.NET.
;; Received 508 bytes from 192.203.230.10#53(E.ROOT-SERVERS.NET) in 68  
ms

capitalone.com.		172800	IN	NS	ns1.capitalone.com.
capitalone.com.		172800	IN	NS	ns2.capitalone.com.
capitalone.com.		172800	IN	NS	ns3.capitalone.com.
;; Received 138 bytes from 192.52.178.30#53(K.GTLD-SERVERS.NET) in 130  
ms

www.capitalone.com.	120	IN	CNAME	www.wpex.capitalone.com.
wpex.capitalone.com.	3600	IN	NS	ns2-mockingbird.wpex.capitalone.com.
wpex.capitalone.com.	3600	IN	NS	ns1-cardinal.wpex.capitalone.com.
;; Received 148 bytes from 199.244.214.107#53(ns3.capitalone.com) in  
42 ms

  -rich goodson