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I have a resolv.conf on ubuntu 12.04 that looks like this (IP addresses have been changed to nonsense):

search internal.mydomain.com
nameserver 205.169.169.193

That nameserver is not authoritative for mydomain.com, but does contain valid records for internal.mydomain.com. I can issue both host and nslookup queries with this resolv.conf without issue:

$ host myserver
myserver.internal.mydomain.com has address 10.1.1.3

$ nslookup myserver
Server:         205.169.169.193
Address:        205.169.169.193

Name:   myserver.internal.mydomain.com
Address: 10.1.1.3

Everything works great, but that nameserver lives in AWS's Route53 can't recurse, so it can't resolve, say, google.com.

So I added another nameserver. Specifically, the stock AWS nameserver used by my ubuntu image on instantiation. I know it works just fine:

search internal.mydomain.com
nameserver 205.169.169.193
nameserver 172.152.152.112

Now, when I run nslookup, it queries the first nameserver, as I'd expect, but fails to find the record, moving onto the 172.* server:

$ nslookup myserver
;; Got recursion not available from 205.169.169.193, trying next server
;; Got recursion not available from 205.169.169.193, trying next server
Server:         172.152.152.112
Address:        172.152.152.112#53

** server can't find myserver: NXDOMAIN

I'm puzzled. Why does resolv.conf behave correctly when I have a single nameserver record, but incorrectly when I have more than one?

Notably this works as I'd expect it on Amazon's linux, v3.4.73-64.112.amzn1.x86_64 (mockbuild@gobi-build-31003). Is this a bug in ubuntu 12.04?

  • What does host myserver do in the second case? – jdthood Mar 15 '14 at 17:25

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