DNS (A 1.0.0.0) problem with DSL

Here's one I can't quite figure out:

Qwest DSL with ActionTec GT701-wg (which runs Linux).
Under Windows, works great.
Under Linux, works great so long as I don't have to go to the secondary
DNS server (i.e. websites such as www.novell.com work fine,
gmail.google.com are unreachable).

My resolv.conf looks like this after DHCP assigns my Linux box an addy:
; generated by /sbin/dhclient-script
search domain.actdsltmp
nameserver 192.168.0.1
nameserver 216.190.127.1

If I switch the last two lines, the problem goes away:
nameserver 216.190.127.1
nameserver 192.168.0.1

If I leave them as is, I get stuff like this in ethereal, and most of
the web is inaccessible:
IP 192.168.0.2 > 192.168.0.1: 19549+ AAAA? gmail.google.com. (34)
IP 192.168.0.1 > 192.168.0.2: 19549 1/1/0 CNAME
gmail.google.akadns.net.
IP 192.168.0.2 > 192.168.0.1: 19550+ A? gmail.google.com. (34)
IP 192.168.0.1 > 192.168.0.2: 19550- 1/0/0 A 1.0.0.0 (50)
IP 192.168.0.2 > 192.168.0.1: 19551+ PTR? 0.0.0.1.in-addr.arpa. (38)
IP 192.168.0.1 > 192.168.0.2: 19551 ServFail- 0/0/0 (38)
IP 192.168.0.2 > 216.190.127.1: 19551+ PTR? 0.0.0.1.in-addr.arpa. (38)
IP 216.190.127.1 > 192.168.0.2: 19551 NXDomain 0/1/0 (102)
IP 192.168.0.2 > 192.168.0.1: 19552+ AAAA? gmail.google.com. (34)
IP 192.168.0.1 > 192.168.0.2: 19552 1/1/0 CNAME
gmail.google.akadns.net.
IP 192.168.0.2 > 1.0.0.0: S 2605997894:2605997894(0) win 5840 <mss
1460,sac
IP 192.168.0.2 > 1.0.0.0: S 2605997894:2605997894(0) win 5840 <mss
1460,sac
IP 192.168.0.2 > 1.0.0.0: S 2605997894:2605997894(0) win 5840 <mss
1460,sac
IP 209.210.46.133 > 192.168.0.2: icmp 36: host 1.0.0.0 unreachable

Any ideas about what's going on here? Why doesn't my box seem to
understand that it should try the secondary DNS source to find gmail?
Tips on fixing this (other than writing a script that changes
resolv.conf everytime my DHCP lease is renewed)?

Thanks,
Lenny

On 2004-12-09, Lenny G. <(E-Mail Removed)> wrote:
> understand that it should try the secondary DNS source to find gmail?

He will try the secondary DNS only if the primary is unreachable, and
the primary works (as far as you showed). But it looks like is
misconfigured and doesn't really work well.

> Tips on fixing this (other than writing a script that changes
> resolv.conf everytime my DHCP lease is renewed)?

Fixing your DNS?
Changing your dhcp server configuration to provide only ONE dns
server? The one that works?

Davide

--
Myth: Linux has a lower TCO
Fact: If you consider that buying NT licenses for business use is
tax-deductible, as are all those tech support calls, NT actually has a
lower TCO than Linux! How are you going to expense software that doesn't
cost anything? Eh?!?

On 8 Dec 2004 23:51:25 -0800, Lenny G. wrote:
> Here's one I can't quite figure out:
>
> My resolv.conf looks like this after DHCP assigns my Linux box an addy:
> ; generated by /sbin/dhclient-script
> search domain.actdsltmp
> nameserver 192.168.0.1
> nameserver 216.190.127.1

Please read http://www.catb.org/~esr/faqs/smart-questions.html
Always provide distribution and release level when posting questions.
It could help you get better answers.

try
service tmdns stop
chkconfig --del tmdns

Then remove the 192.168.0.1 line in /etc/resolv.conf

service network restart
cat /etc/resolv.conf

Thanks for the tips.

Distro/Release: Redhat FC 2. The machines IP, if you didn't already
infer, is 192.168.0.2. The DSL Modem is .0.1. The other resolv.conf
entry is the ISPs DNS server, as relayed through DHCP.

'service tmdns stop' results in "tmdns: unrecognized service," so I
didn't bother with '-del tmdns'.

Removing 192.168.0.1 does indeed work (it has the same effect as moving
the ISPs DNS server above it in precedence), but the benefit of this is
negated by the fact that everytime the machine boots and everytime the
connection expires and everytime the lease renews, .0.1 pops back in
front.

Any idea about what the right response of my machine should be when it
receives the "1/0/0 A 1.0.0.0" packet back from 192.168.0.1 -- I think
at this point (or somewhere near here in the trace provided previously)
192.168.0.2 should ask the secondary DNS server, but it never does...
Or am I misunderstanding .0.1's responses?

> He will try the secondary DNS only if the primary is
> unreachable, and
> the primary works (as far as you showed). But it looks like is
> misconfigured and doesn't really work well.

I need to take a trace of this same action under windows; I think the
responses from 192.168.0.1 are identical, and yet the computer manages
to successfully query the secondary DNS (*consider this pure conjecture
until I actually take the trace...)

> Fixing your DNS?
> Changing your dhcp server configuration to provide only
> ONE dns
> server? The one that works?

Maybe you can point me in the right direction for going down this
path. As far as I can tell, the GT701-wg modem doesn't expose this
functionality in its dhcp server. I can edit it on the client side in
/etc/resolv.conf, but this is a bit of a non-starter since I won't
expect (or want, yikes!) my kids or other members of the house to have
the superuser privileges neccessary to do this everytime they turn on
the machine, or everytime the connection gets dropped, or everytime the
dhcp lease gets renewed, ...
Thanks for the help -- I'll get this figured out yet!

-- Lenny

"Lenny G." <(E-Mail Removed)> said:
>Here's one I can't quite figure out:
>Qwest DSL with ActionTec GT701-wg (which runs Linux).
>Under Windows, works great.
>Under Linux, works great so long as I don't have to go to the secondary
>DNS server (i.e. websites such as www.novell.com work fine,
>gmail.google.com are unreachable).
....
>If I leave them as is, I get stuff like this in ethereal, and most of
>the web is inaccessible:
>IP 192.168.0.2 > 192.168.0.1: 19549+ AAAA? gmail.google.com. (34)

This looks like an DNS6 (or what it is; anyway the IPv6 extensions for
DNS) query. You might try to find if you can disable this and use just
plain traditional DNS.
--
Wolf a.k.a. Juha Laiho Espoo, Finland
(GC 3.0) GIT d- s+: a C++ ULSH++++$ P++@ L+++ E- W+$@ N++ !K w !O !M V
PS(+) PE Y+ PGP(+) t- 5 !X R !tv b+ !DI D G e+ h---- r+++ y++++
"...cancel my subscription to the resurrection!" (Jim Morrison)

> This looks like an DNS6 (or what it is; anyway the IPv6 extensions
> for DNS) query. You might try to find if you can disable this and use

> just plain traditional DNS.

This is very insightful. I did notice that ifconfig showed eth0 with
both a v4 and a v6 address, so I went ahead and enabled v6 in the
config for eth0 but nothing seemed to change.

It doesn't look like there is a way to turn my DSL modem's v6 DNS
feature off (to v4). But since both the modem and my computer run
Linux, shouldn't I be able to configure something on my box to
correctly interpret the DNS6 packets? Any idea where I might find some
info on this?

Thanks!
Lenny

> Myth: Linux has a lower TCO
> Fact: If you consider that buying NT licenses for business use is
> tax-deductible, as are all those tech support calls, NT actually has a
> lower TCO than Linux! How are you going to expense software that doesn't
> cost anything? Eh?!?

That's lame.

So with NT you spend money on lic and support and pay 25% of that money
spent less in taxes. Let's see an example:

let's say that your lic and support for NT cost $20,000 for a year. So now
you take that as an expense and don't pay tax on that so that saves you
roughly $5,000, you neted a total of -$15,000 ($20,000 spent minus $5,000
saved in taxes).

With linux there was no cost so you saved the entire $20,000 and paid taxes
on it, roughly $5,000. So you neted a total of +15,000.

That's a $30,000 difference. Your company could have bought a datacenter
full of equipment for that amount of money.

I hope you're not in charge of the finances for your company. With lamer
advice like this small companies go broke and big ones end up like enron.

Wake up. M$ will never make more sense than Linux.

I'll bet you take out a home mortgage so you can pay the bank an extra
$10,000 in interest per year so you don't have to pay taxes on that money,
saving you $2,500 but putting you in the hole by $7,500 a year.

L-)

> Qwest DSL with ActionTec GT701-wg (which runs Linux).
> Under Windows, works great.
> Under Linux, works great so long as I don't have to go to the secondary

Hmmm. Reading your post, don't you mean "works great if I force it to go to
the secondary"?

> My resolv.conf looks like this after DHCP assigns my Linux box an addy:
> ; generated by /sbin/dhclient-script
> search domain.actdsltmp
> nameserver 192.168.0.1
> nameserver 216.190.127.1

Looks like either your /sbin/dhclient-script throws in the extranious entry
(probably set up for you to have an internal DNS cache) or your ISP is
putting in it's own internal cache server. Since you say it works in
windows my guess would be your /sbin/dhclient-script. Why not go edit it
and see how it actually builds your resolv.conf file? It may also be
pulling this 192.168 address from another conf file related to your dhcp
client, check it out.

As a last resort you can always setup the resolv.conf file the way that
works and then chmod it so that the dhcp client can't write to it.

"/dev/null" <(E-Mail Removed)> writes:

>> Myth: Linux has a lower TCO
>> Fact: If you consider that buying NT licenses for business use is
>> tax-deductible, as are all those tech support calls, NT actually has a
>> lower TCO than Linux! How are you going to expense software that doesn't
>> cost anything? Eh?!?

>That's lame.

>So with NT you spend money on lic and support and pay 25% of that money
>spent less in taxes. Let's see an example:

>let's say that your lic and support for NT cost $20,000 for a year. So now
>you take that as an expense and don't pay tax on that so that saves you
>roughly $5,000, you neted a total of -$15,000 ($20,000 spent minus $5,000
>saved in taxes).

NO very bad economics. You did not pay the tax on that 20000 you did not
spend. That is not a cost to you. While your analysis of the NT software
was fine, you cannot have it both ways. Either in the NT case you spent
25000 (20000 on NT and 5000 on tax) and got back 5000, or you ignore the
tax that you paid and count the saving in tax as a grant from the gov't (
20000-5000 grant=15000) in which case Linux costs you nothing. Ie the
difference between the cost of Linux and the cost of NT is 15000, not
10000.



>With linux there was no cost so you saved the entire $20,000 and paid taxes
>on it, roughly $5,000. So you neted a total of +15,000.

>That's a $30,000 difference. Your company could have bought a datacenter
>full of equipment for that amount of money.

That is even more rediculous. The difference is $15000. no matter how you
calculate it. A saving is not a cash infusion. You did NOT net a total of
$15000 in the Linux case.


>I hope you're not in charge of the finances for your company. With lamer
>advice like this small companies go broke and big ones end up like enron.

I hope you are not either. Yes, NT costs more, but your economics is silly.

>Wake up. M$ will never make more sense than Linux.