DNS via Linksys ADSL2MUE modem not working properly

[Neil Woolford]

Lea Gris <lea.gris <at> noiraude.net> writes:

> 
> Neil Woolford a écrit :

> > 
I connect to broadband via a Linksys ADSL2MUE modem, at 192.168.1.1.  The modem
is set to provide DHCP and correctly sets itself to the DNS address settings of
my ISP.  When connected to my ancient laptop running windows 98SE, the modem
provides a reliable DNS service under its own address (192.168.1.1).
> 
Under Ubuntu (Hoary, Breezy and Dapper so far) the DNS Server is automatically
set  to that address (192.168.1.1).  However, applications such as Firefox and
Update Manager just hang as they appear not to be able to access any DNS Server.

> 
> At a glance there is a non conformance of DNS replies from the ADSL2MUE 
> modem at IP 192.168.1.1. It may be a DNS proxy forwarder or cache. I 
> don't know. What you may be able to achieve is configure the ADSL2MUE 
> modem to not act as a DNS proxy service.

I think it probably proxy forwards, as it isn't a device with a big memory.  It
could well be that it doesn't provide the service in a 100% correct manner.  The
device is good at what it does, but not flexible;  if you want what it does,
then fine, otherwise you can't change things.
> 
> Alternatively you can investigate that it may be related to ipv6 
> incompatibility of the DNS proxy service of the ADSL2MUE :

Nice idea...

> 
> than dig some names with traces to show what's happening wrong.
> 
> Firefox and many other application trys to get ipv6 AAAA records from 
> DNS to join servers preferably in ipv6. Since ipv6 is enabled in Ubuntu 
> but may not be supported by the DNS forwarder of the ADSL2MUE :
> 
> # forcing ipv4 querries
> dig -4 example.com  <at> 192.168.1.1 +trace
> 
> # forcing ipv6 querries
> dig -6 example.com  <at> 192.168.1.1 +trace
> 
Ipv4 and ipv6 both worked fine from dig, though using the trace option caused it
to fail for both.
> 
> If that is the problem then you will have to disable ipv6 in Ubuntu.
> 
> To disable ipv6 do:
> 
> sudo gedit /etc/modprobe.d/aliases
> 
> find a line with alias net-pf-10 ipv6 or alike
> comment out the line with a #
> add a line with:
> alias net-pf-10 off
> 
> save the file
> 
> At next reboot ipv6 support from the kernel will be disabled.
> 

Tried it anyway, but no luck.

Neil