Bind9 sudden failure to resolve certain domains.

[Jose R R]

Good day all-

I have now upgraded to Bind9 9.4.3-P3 due to the DoS vulnerability (<
http://lwn.net/Articles/344008/rss >).  However this upgrade has not
"cured" the fact that approximately on July 27, 2009, my Bind9 prior
version in that server stopped resolving domain names with rDNS
74.208.x.x --without any obvious reason.  As a matter of fact, from
within that server environment I am not able to ping domains within
that IP block.

Performing an intensive nmap scan of one IP in that domain, saving the
results into an XML file, and subsequently feeding that file to zenmap
(< http://nmap.org/zenmap/ >) shows a broken connection from this
particular server to the IP in the 74.208.x.x block.

nmap -T4 -A -v -PE -PS22,25,80 -PA21,23,80,3389 -oX
nmap_74.208.x.x.xml 74.208.x.x

As a result I have added an OpenDNS name server to fulfill the role of
slave since the issue appears to be local to the server.  Any
ideas/suggestion on what may be causing this issue will be welcomed.

Thanks in advance for your consideration.



--
Jose R R
http://www.metztli-it.com
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