Strange IPv6 DNS lookups

[Reber, Simon]

Hey Kenneth,

Try to fully disable IPv6 while adding:

	alias net-pf-10 off
	alias ipv6 off

to /etc/modprobe.conf and to /etc/sysconfig/network

	NETWORKING_IPV6=no

This should probably solve the problem (at least IPv6 is turned off)

Cheers,
Si

>-----Original Message-----
>From: redhat-list-bounces at redhat.com 
>[mailto:redhat-list-bounces at redhat.com] On Behalf Of Kenneth Holter
>Sent: Monday, March 09, 2009 4:17 PM
>To: redhat-list at redhat.com
>Subject: Strange IPv6 DNS lookups
>
>Hello all.
>
>
>Several of our RHEL-servers are issuing strange DNS lookups. 
>Consider this
>example:
>
>
>*  1   0.000000   1.2.3.4 -> 5.6.7.8   DNS Standard query AAAA **
>server1.example-prod.com* <http://server1.example-prod.com/>*
>  9   0.007891   1.2.3.4 -> 5.6.7.8   DNS Standard query AAAA
>server1.example-prod.com.example-test.local
> 11   0.092904   1.2.3.4 -> 5.6.7.82   DNS Standard query A
>server1.example-prod.com
> 12   0.093356   5.6.7.8 -> 1.2.3.4   DNS Standard query 
>response A 1.2.3.4
>*
>
>>From what I can tell, the client first issues two IPv6 DNS 
>lookups, before
>falling back to IPv4 lookup. We're not running IPv6 (and our 
>DNS servers do
>not support IPv6 lookups), so the client is not getting and 
>answer before
>issuing the IPv4 lookup.
>
>I've very puzzled by the second query, in which the FQDN of 
>the lookup query
>is appended another domain. I've noticed that the appended 
>domain may be
>both the same domain name (i.e. 
>server1.example-prod-com.example-prod.com)
>or another domain as in the example above.
>Does anyone have a clue as to why such bizarre queries are 
>performed by the
>client?
>
>Since we're not running IPv6, I have simply disabled it for this server
>(grepping "lsmod" does not return any "ipv6" results). Yet the problem
>remains. Does the DNS lookup library automatically issue IPv6 
>queries before
>issuing IPv4 queries? Is there a way to disable IPv6 lookups?
>
>
>Regards,
>Kenneth Holter
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