Why can't get name from DNS

Dear RedHat gurus,

I am new to Linux, so every step is pain for me. Hope can get some help from
experts here.

I setup a Redhat 9 box at home and try to hook up it to internet through my
ISP (Road Runner under Time Warner), using DHCP connection. I succeeded in
making it see internet. I can ping yahoo.com through its IP, but can't ping
the name itself. The Mozilla can not see any internet site. From Network
Configuration box, I can see the primary, secondary, and tertiary DNS (from
ISP) automatically setup and they are correct.

Why I can not ping yahoo.com on my Linux box? I have no such problems with
my other PCs hooked up to the same router. Is that possible my ISP's DNSs do
not support request from Linux box? I call them about this, they said they
do not support Linux and simply refuse to give any more details.

Appreciate any help.

--
Allen Guan
281-489-2314

On Sun, 12 Oct 2003 22:21:00 +0000, Yun Guan wrote:

> Dear RedHat gurus,
>
> I am new to Linux, so every step is pain for me. Hope can get some help from
> experts here.
>
> I setup a Redhat 9 box at home and try to hook up it to internet through my
> ISP (Road Runner under Time Warner), using DHCP connection. I succeeded in
> making it see internet. I can ping yahoo.com through its IP, but can't ping
> the name itself. The Mozilla can not see any internet site. From Network
> Configuration box, I can see the primary, secondary, and tertiary DNS (from
> ISP) automatically setup and they are correct.
>
> Why I can not ping yahoo.com on my Linux box? I have no such problems with
> my other PCs hooked up to the same router. Is that possible my ISP's DNSs do
> not support request from Linux box? I call them about this, they said they
> do not support Linux and simply refuse to give any more details.
>
> Appreciate any help.


/etc/resolv.conf

lists the dns servers like this


nameserver 142.77.1.1
nameserver 142.77.1.5



To edit file: login as root.
then edit using a text editor : gedit, Kwrite, Kate.

Yun Guan wrote:
>
> Dear RedHat gurus,
>
> I am new to Linux, so every step is pain for me. Hope can get some help from
> experts here.
>
> I setup a Redhat 9 box at home and try to hook up it to internet through my
> ISP (Road Runner under Time Warner), using DHCP connection. I succeeded in
> making it see internet. I can ping yahoo.com through its IP, but can't ping
> the name itself. The Mozilla can not see any internet site. From Network
> Configuration box, I can see the primary, secondary, and tertiary DNS (from
> ISP) automatically setup and they are correct.
>
> Why I can not ping yahoo.com on my Linux box? I have no such problems with
> my other PCs hooked up to the same router. Is that possible my ISP's DNSs do
> not support request from Linux box?

No. DNS is a general standard, it does not specify an OS. It is not
possible to determine what OS a machine which issued a DNS query is
running (not from the DNS query anyway).

Have a look at /etc/resolv.conf while you are connected and see if the
correct nameservers are listed there. If they are not, as a first step
try editing the file manually and inserting them and see if that helps.
If that does it, you need to work out why the DHCP client isn't updating
/etc/resolv.conf.

Also check /etc/nsswitch.conf and ensure that the "hosts:" line contains
"dns".

And make sure you aren't running a firewall which blocks UDP. Most
Internet traffic, including HTTP, is TCP but DNS is normally UDP.

Regards, Ian

Yes, it is a firewall issue. Under "Security level High", and "Use default
firewall rules", it can not get DNS reply, even though the documentations
say it can. After I check Customize and check Allow incoming WWW/HTTP and
DHCP. I can see the DNS now.

Thanks a lot for the hint.

"Ian Northeast" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Yun Guan wrote:
> >
> > Dear RedHat gurus,
> >
> > I am new to Linux, so every step is pain for me. Hope can get some help
from
> > experts here.
> >
> > I setup a Redhat 9 box at home and try to hook up it to internet through
my
> > ISP (Road Runner under Time Warner), using DHCP connection. I succeeded
in
> > making it see internet. I can ping yahoo.com through its IP, but can't
ping
> > the name itself. The Mozilla can not see any internet site. From Network
> > Configuration box, I can see the primary, secondary, and tertiary DNS
(from
> > ISP) automatically setup and they are correct.
> >
> > Why I can not ping yahoo.com on my Linux box? I have no such problems
with
> > my other PCs hooked up to the same router. Is that possible my ISP's
DNSs do
> > not support request from Linux box?
>
> No. DNS is a general standard, it does not specify an OS. It is not
> possible to determine what OS a machine which issued a DNS query is
> running (not from the DNS query anyway).
>
> Have a look at /etc/resolv.conf while you are connected and see if the
> correct nameservers are listed there. If they are not, as a first step
> try editing the file manually and inserting them and see if that helps.
> If that does it, you need to work out why the DHCP client isn't updating
> /etc/resolv.conf.
>
> Also check /etc/nsswitch.conf and ensure that the "hosts:" line contains
> "dns".
>
> And make sure you aren't running a firewall which blocks UDP. Most
> Internet traffic, including HTTP, is TCP but DNS is normally UDP.
>
> Regards, Ian

On Mon, 13 Oct 2003 01:41:57 +0000, Yun Guan wrote:

> Yes, it is a firewall issue. Under "Security level High", and "Use default
> firewall rules", it can not get DNS reply, even though the documentations
> say it can. After I check Customize and check Allow incoming WWW/HTTP and
> DHCP. I can see the DNS now.
>
> Thanks a lot for the hint.


You can also just install DNS and the DNS cache rpms and setup your own
caching DNS server. Works much better than hitting those over loaded
crappy ISP DNS servers.