Need help with a DNS problem

[Allen Winter]

Hi,

A few months ago I posted the enclosed message and was given the fix to turn off ipv6
support,
which has worked fine for me ever since (i.e, add the line 'install ipv6
/bin/true' to /etc/modprobe.conf)

Recently the DNS problems I described have come back... I did upgrade a new kernel using
yum.
I still see the ipv6 line in my /etc/modprobe.conf file so I am at a loss.  Any ideas as
to what may
be causing resolver "dropouts"??

Regards and Help!
Allen
-------------------

Subject: Need help with a DNS problem
Date: Friday 04 June 2004 01:04 pm
From: Allen Winter <winterz(a)verizon.net&gt;
To: For users of Fedora Core releases <fedora-list(a)redhat.com&gt;

Howdy,

I am having a strange issue on my new Fedora Core 2 install with DNS.

I have three systems connected to ADSL via a Netgear WGR214v2 Router,
with one running Redhat 9, one running FC1, and the other my new FC2 system.

The Redhat system is running dhcpcd and has no problem getting addresses.
The FC1 system is running dhclient and had no problem getting addresses.

The new FC2 system is also running dhclient and fails to get addresses for only
a *few* names I've encountered so far.  And dig will give me an answer for those
names, but nslookup will fail.  I have looked up everything I know and compared
the FC1 and FC2 systems and they look to be configured the same. 

For example,
% dig myfidelity.members.fidelity.com

; <<>> DiG 9.2.3 <<>> myfidelity.members.fidelity.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 3837
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;myfidelity.members.fidelity.com. IN    A

;; ANSWER SECTION:
myfidelity.members.fidelity.com. 6056 IN CNAME  myfidelity.members.retail.fidelity.com.

;; AUTHORITY SECTION:
retail.fidelity.com.    52      IN      SOA     dns3dccfw01.fidelity.com.
hostmaster.retail.fidelity.com. 2004060332 10800 3600 604800 60

;; Query time: 25 msec
;; SERVER: 192.168.0.1#53(192.168.0.1)
;; WHEN: Fri Jun  4 13:01:26 2004
;; MSG SIZE  rcvd: 148

% nslookup myfidelity.members.fidelity.com
Server:         192.168.0.1
Address:        192.168.0.1#53

** server can't find myfidelity.members.fidelity.com: NXDOMAIN

Oh, and I forgot to mention that every now and then nslookup will return an address for
myfidelity.members.fidelity.com,
but that is not the typical case.

Any ideas?
Regards,
Allen


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-------------------------------------------------------

[Yang Xiao]

On Mon, 30 Aug 2004 15:32:40 -0400, Allen Winter <winterz(a)verizon.net&gt; wrote:
>  Hi,
>  
>  A few months ago I posted the enclosed message and was given the fix to turn off ipv6
> support,
>  which has worked fine for me ever since (i.e, add the line 'install ipv6
> /bin/true' to /etc/modprobe.conf)
>  
>  Recently the DNS problems I described have come back... I did upgrade a new kernel using
> yum.
>  I still see the ipv6 line in my /etc/modprobe.conf file so I am at a loss.  Any ideas as
> to what may
>  be causing resolver "dropouts"??
>  
>  Regards and Help!
>  Allen
>  -------------------
>  
>  Subject: Need help with a DNS problem
>  Date: Friday 04 June 2004 01:04 pm
>  From: Allen Winter <winterz(a)verizon.net&gt;
>  To: For users of Fedora Core releases <fedora-list(a)redhat.com&gt;
>  
>  Howdy,
>  
>  I am having a strange issue on my new Fedora Core 2 install with DNS.
>  
>  I have three systems connected to ADSL via a Netgear WGR214v2 Router,
>  with one running Redhat 9, one running FC1, and the other my new FC2 system.
>  
>  The Redhat system is running dhcpcd and has no problem getting addresses.
>  The FC1 system is running dhclient and had no problem getting addresses.
>  
>  The new FC2 system is also running dhclient and fails to get addresses for only
>  a *few* names I've encountered so far.  And dig will give me an answer for those
>  names, but nslookup will fail.  I have looked up everything I know and compared
>  the FC1 and FC2 systems and they look to be configured the same.
>  
>  For example,
>  % dig myfidelity.members.fidelity.com
>  
>  ; <<>> DiG 9.2.3 <<>> myfidelity.members.fidelity.com
>  ;; global options:  printcmd
>  ;; Got answer:
>  ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 3837
>  ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0
>  
>  ;; QUESTION SECTION:
>  ;myfidelity.members.fidelity.com. IN    A
>  
>  ;; ANSWER SECTION:
>  myfidelity.members.fidelity.com. 6056 IN CNAME  myfidelity.members.retail.fidelity.com.
>  
>  ;; AUTHORITY SECTION:
>  retail.fidelity.com.    52      IN      SOA     dns3dccfw01.fidelity.com.
> hostmaster.retail.fidelity.com. 2004060332 10800 3600 604800 60
>  
>  ;; Query time: 25 msec
>  ;; SERVER: 192.168.0.1#53(192.168.0.1)
>  ;; WHEN: Fri Jun  4 13:01:26 2004
>  ;; MSG SIZE  rcvd: 148
>  
>  % nslookup myfidelity.members.fidelity.com
>  Server:         192.168.0.1
>  Address:        192.168.0.1#53
>  
>  ** server can't find myfidelity.members.fidelity.com: NXDOMAIN
>  
>  Oh, and I forgot to mention that every now and then nslookup will return an address for
> myfidelity.members.fidelity.com,
>  but that is not the typical case.
>  
>  Any ideas?
>  Regards,
>  Allen
>  
>  --
>  fedora-list mailing list
>  fedora-list(a)redhat.com
>  To unsubscribe: http://www.redhat.com/mailman/listinfo/fedora-list
>  
>  -------------------------------------------------------
>  
>  --
>  fedora-list mailing list
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>   
what's your /etc/resolv.conf look like?

Yang

[Allen Winter]

On Monday 30 August 2004 05:22 pm, Yang Xiao wrote:
>  On Mon, 30 Aug 2004 15:32:40 -0400, Allen Winter
> <winterz(a)verizon.net&gt; wrote:
>  > Hi,
>  > 
>  > A few months ago I posted the enclosed message and was given the fix to turn off
> ipv6 support,
>  > which has worked fine for me ever since (i.e, add the line 'install ipv6
> /bin/true' to /etc/modprobe.conf)
>  > 
>  > Recently the DNS problems I described have come back... I did upgrade a new kernel
> using yum.
>  > I still see the ipv6 line in my /etc/modprobe.conf file so I am at a loss.  Any
> ideas as to what may
>  > be causing resolver "dropouts"??
>  > 
>  > Regards and Help!
>  > Allen
>  > -------------------
>  > 
>  > Subject: Need help with a DNS problem
>  > Date: Friday 04 June 2004 01:04 pm
>  > From: Allen Winter <winterz(a)verizon.net&gt;
>  > To: For users of Fedora Core releases <fedora-list(a)redhat.com&gt;
>  > 
>  > Howdy,
>  > 
>  > I am having a strange issue on my new Fedora Core 2 install with DNS.
>  > 
>  > I have three systems connected to ADSL via a Netgear WGR214v2 Router,
>  > with one running Redhat 9, one running FC1, and the other my new FC2 system.
>  > 
>  > The Redhat system is running dhcpcd and has no problem getting addresses.
>  > The FC1 system is running dhclient and had no problem getting addresses.
>  > 
>  > The new FC2 system is also running dhclient and fails to get addresses for only
>  > a *few* names I've encountered so far.  And dig will give me an answer for
> those
>  > names, but nslookup will fail.  I have looked up everything I know and compared
>  > the FC1 and FC2 systems and they look to be configured the same.
>  > 
>  > For example,
>  > % dig myfidelity.members.fidelity.com
>  > 
>  > ; <<>> DiG 9.2.3 <<>> myfidelity.members.fidelity.com
>  > ;; global options:  printcmd
>  > ;; Got answer:
>  > ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 3837
>  > ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0
>  > 
>  > ;; QUESTION SECTION:
>  > ;myfidelity.members.fidelity.com. IN    A
>  > 
>  > ;; ANSWER SECTION:
>  > myfidelity.members.fidelity.com. 6056 IN CNAME 
> myfidelity.members.retail.fidelity.com.
>  > 
>  > ;; AUTHORITY SECTION:
>  > retail.fidelity.com.    52      IN      SOA     dns3dccfw01.fidelity.com.
> hostmaster.retail.fidelity.com. 2004060332 10800 3600 604800 60
>  > 
>  > ;; Query time: 25 msec
>  > ;; SERVER: 192.168.0.1#53(192.168.0.1)
>  > ;; WHEN: Fri Jun  4 13:01:26 2004
>  > ;; MSG SIZE  rcvd: 148
>  > 
>  > % nslookup myfidelity.members.fidelity.com
>  > Server:         192.168.0.1
>  > Address:        192.168.0.1#53
>  > 
>  > ** server can't find myfidelity.members.fidelity.com: NXDOMAIN
>  > 
>  > Oh, and I forgot to mention that every now and then nslookup will return an address
> for myfidelity.members.fidelity.com,
>  > but that is not the typical case.
>  > 
>  > Any ideas?
>  > Regards,
>  > Allen
>  > 
>  > --
>  > fedora-list mailing list
>  > fedora-list(a)redhat.com
>  > To unsubscribe: http://www.redhat.com/mailman/listinfo/fedora-list
>  > 
>  > -------------------------------------------------------
>  > 
>  > --
>  > fedora-list mailing list
>  > fedora-list(a)redhat.com
>  > To unsubscribe: http://www.redhat.com/mailman/listinfo/fedora-list
>  > 
>  what's your /etc/resolv.conf look like?
>   
% cat /etc/resolv.conf
; generated by /sbin/dhclient-script
nameserver 192.168.0.1

[Kenneth Porter]

--On Monday, August 30, 2004 5:23 PM -0400 Allen Winter 
<winterz(a)verizon.net&gt; wrote:

>  % cat /etc/resolv.conf
>  ; generated by /sbin/dhclient-script
>  nameserver 192.168.0.1 
That looks like the typical address supplied by a consumer router, so it 
must be your Netgear. If dig works but nslookup doesn't, it's usually 
because the DNS server isn't supplying answers for your reverse zone. 
That's not uncommon in a consumer router, but check if Netgear has newer 
firmware to address that. nslookup, unlike dig, will try to resolve a name 
for the name server, and lack of reverse lookups makes that fail. Yet 
another reason that nslookup is deprecated. The Netgear should provide a 
reverse zone for 192.168.0.0/24, possibly with synthesized names.

[Alexander Dalloz]

Am Mo, den 30.08.2004 schrieb Allen Winter um 21:32:

>  I have three systems connected to ADSL via a Netgear WGR214v2
> Router,
>  with one running Redhat 9, one running FC1, and the other my new FC2 system.
>  
>  The Redhat system is running dhcpcd and has no problem getting addresses.
>  The FC1 system is running dhclient and had no problem getting addresses.
>  
>  The new FC2 system is also running dhclient and fails to get addresses for only
>  a *few* names I've encountered so far.  And dig will give me an answer for those
>  names, but nslookup will fail.  I have looked up everything I know and compared
>  the FC1 and FC2 systems and they look to be configured the same.  
Try following settings:

echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
echo 0 > /proc/sys/net/ipv4/tcp_moderate_rcvbuf

Do you have any iptables settings active on the FC2 machine?


-- 
Alexander Dalloz | Enger, Germany | GPG key 1024D/ED695653 1999-07-13
Fedora GNU/Linux Core 2 (Tettnang) kernel 2.6.8-1.521smp 
Serendipity 23:40:03 up 20:56, 12 users, 0.07, 0.20, 0.26