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How do I troubleshoot DNS peculiarites?

Last response: in Wireless Networking
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Anonymous
December 13, 2004 12:14:14 AM

Archived from groups: alt.internet.wireless (More info?)

I just installed a Netgear WGR614v4 54g router, latest firmware V5.0_02
pre-installed. I cloned my MAC address and connected to cable modem.
I had previously been running an SMC7004WFW-802.11b router against this
same cable modem. (The wireless in that one started dying occasionally, but
I don't think I ever had a DNS issue.)

Both my wired desktop and Netgear WG511 54g wireless laptop are having the
same DNS problem:
Some sites resolve just fine, and I can ping or surf.
Other sites don't resolve. some resolve, but too late for a web page.
(I ping after the web fails and it's okay, and then I can surf.)

Occasionally, a site that worked fails.
It seems that I can ipconfig /flushdns and then the sites all seem to work.

Something is a little snarky and I don't know where to look, exactly.
tracert will tell me where routing breaks down, but if I can't resolve a
hostname, how do I know where to place blame?

Windows XP - SP2 on both desktop(home) and laptop(pro).
The DHCP-supplied DNS is the address of the router. I suppose I could
adjust that temporarily to the address supplied to the router, but I like
default setups that work ;-(

I've power cycled the cable modem and router, and rebooted the laptop and
desktop. No change.




side note: handy feature on this router. It has a redirected home page so
that as soon as I brought up a browser, I found myself at a router config
page. I didn't have to put in the address of the router. When I finished
basic config, it told me this config page wouldn't show up in the future.

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5
Anonymous
December 13, 2004 12:14:15 AM

Archived from groups: alt.internet.wireless (More info?)

<dold@XHowXdoXIX.usenet.us.com> wrote in message
news:cpicb6$rqs$1@blue.rahul.net...
> I just installed a Netgear WGR614v4 54g router, latest firmware V5.0_02
> pre-installed. I cloned my MAC address and connected to cable modem.
> I had previously been running an SMC7004WFW-802.11b router against this
> same cable modem. (The wireless in that one started dying occasionally,
but
> I don't think I ever had a DNS issue.)
>
> Both my wired desktop and Netgear WG511 54g wireless laptop are having the
> same DNS problem:
> Some sites resolve just fine, and I can ping or surf.
> Other sites don't resolve. some resolve, but too late for a web page.
> (I ping after the web fails and it's okay, and then I can surf.)
>
> Occasionally, a site that worked fails.
> It seems that I can ipconfig /flushdns and then the sites all seem to
work.
>
> Something is a little snarky and I don't know where to look, exactly.
> tracert will tell me where routing breaks down, but if I can't resolve a
> hostname, how do I know where to place blame?
>
> Windows XP - SP2 on both desktop(home) and laptop(pro).
> The DHCP-supplied DNS is the address of the router. I suppose I could
> adjust that temporarily to the address supplied to the router, but I like
> default setups that work ;-(

The DNS should be set to those provided by your ISP (usually 2 of them)
The DNS shouldnt be the address of the router.
I would reset the the thing to factory default, turn off your modem and
router,
power up the modem,, wait a minute or so then power up the router.
If you have the router config to automatically get DHCP it should all config
and work without doing anything.....at least that is my experience.
and Im sticking to it


>
> I've power cycled the cable modem and router, and rebooted the laptop and
> desktop. No change.
>
>
>
>
> side note: handy feature on this router. It has a redirected home page
so
> that as soon as I brought up a browser, I found myself at a router config
> page. I didn't have to put in the address of the router. When I finished
> basic config, it told me this config page wouldn't show up in the future.
>
> --
> ---
> Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5
>
Anonymous
December 13, 2004 3:50:45 AM

Archived from groups: alt.internet.wireless (More info?)

Airhead <campbell@alliancecable.net> wrote:
> The DNS should be set to those provided by your ISP (usually 2 of them)
> The DNS shouldnt be the address of the router.

Several routers that I've worked with, including the SMC that I just
replaced, and apparently, this Netgear, provide their own address as the
DNS server.

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5
Related resources
Anonymous
December 13, 2004 3:50:46 AM

Archived from groups: alt.internet.wireless (More info?)

On Mon, 13 Dec 2004 00:50:45 +0000 (UTC), dold@XReXXHowXd.usenet.us.com
spoketh

>Airhead <campbell@alliancecable.net> wrote:
>> The DNS should be set to those provided by your ISP (usually 2 of them)
>> The DNS shouldnt be the address of the router.
>
>Several routers that I've worked with, including the SMC that I just
>replaced, and apparently, this Netgear, provide their own address as the
>DNS server.

And there is absolutely nothing wrong with that. The router simply
forwards the request on to one of the two DNS servers it has in its list
that was received when it got it's DHCP lease from the ISP. This is an
easy way of ensuring that the LAN clients doesn't have to worry about
what the DNS server addresses are, or if they have changed. Since many
people doesn't use dynamic addresses on their LANs, it would be a real
hassle to keep up with any DNS server changes...


Lars M. Hansen
http://www.hansenonline.net
(replace 'badnews' with 'news' in e-mail address)
Anonymous
December 13, 2004 7:42:41 AM

Archived from groups: alt.internet.wireless (More info?)

Lars M. Hansen <badnews@hansenonline.net> wrote:
> And there is absolutely nothing wrong with that. The router simply
> forwards the request on to one of the two DNS servers it has in its list
> that was received when it got it's DHCP lease from the ISP. This is an

That seemed to work well with the SMC, but it's not happening smoothly with
the Netgear tonight. I had a Netgear 814 for a few days, and didn't notice
any DNS trouble. It also referenced itself as DNS for DHCP clients.

I changed to a static definition of an outside DNS server on my laptop, and
it seems to be okay. With the DHCP-provided netgear as DNS, I could ping
one server in a domain, but not others, then I could, then not...

I just haven't deciphered whether it is the fault of the Netgear, or of one
of the MCHSI.COM servers that are provided to the Netgear by DHCP.

204.127.202.4 ns5.attbi.com
216.148.227.68 ns2.attbi.com

I think I'll plug my stable address into the Netgear, instead of using the
DHCP supplied addresses, and see what happens.

Hmmm. Maybe that's it. attbi just isn't stable for me.
Plugging in the dns from my favored ISP, instead of the DHCP-supplied
address into the router config gives me the router as the DNS address at my
PC, but it seems to be working well.

I might change back to DHCP-supplied in the router later.
Other than manually testing different addresses, I don't know what tool to
use to investigate this problem.

---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5
Anonymous
December 13, 2004 11:18:31 AM

Archived from groups: alt.internet.wireless (More info?)

dold@XReXXHowXd.usenet.us.com wrote:
>
> Hmmm. Maybe that's it. attbi just isn't stable for me.
> Plugging in the dns from my favored ISP, instead of the DHCP-supplied
> address into the router config gives me the router as the DNS address
> at my PC, but it seems to be working well.
>
> I might change back to DHCP-supplied in the router later.
> Other than manually testing different addresses, I don't know what
> tool to use to investigate this problem.
>
My WGR614v4 is working fine for me with the DHCP-supplied DNS address. But
I have long since given up on DNS working reliably from my ISP, and use a
DNS caching program now. There are a number of freeware ones, but ExtraDNS
is the best I have found, even if not free. But you have to run it as
Administrator if using Win2K/XP.
Anonymous
December 13, 2004 2:20:17 PM

Archived from groups: alt.internet.wireless (More info?)

I would recommend running services.msc from the Start|Run box and
observing whether or not the DNS Client service is running (likely it is). I
routinely stop that service and set it to disabled - this is the client side
caching dns client that caches not only good dns replies, but also caches
dns lookup failures. Caching failures may not be such a smart thing to do
IMHO - especially if you are using your ISP's dns servers which may be
overloaded and therefore busy and unresponsive.

HTH



<dold@XHowXdoXIX.usenet.us.com> wrote in message
news:cpicb6$rqs$1@blue.rahul.net...
> I just installed a Netgear WGR614v4 54g router, latest firmware V5.0_02
> pre-installed. I cloned my MAC address and connected to cable modem.
> I had previously been running an SMC7004WFW-802.11b router against this
> same cable modem. (The wireless in that one started dying occasionally,
but
> I don't think I ever had a DNS issue.)
>
> Both my wired desktop and Netgear WG511 54g wireless laptop are having the
> same DNS problem:
> Some sites resolve just fine, and I can ping or surf.
> Other sites don't resolve. some resolve, but too late for a web page.
> (I ping after the web fails and it's okay, and then I can surf.)
>
> Occasionally, a site that worked fails.
> It seems that I can ipconfig /flushdns and then the sites all seem to
work.
>
> Something is a little snarky and I don't know where to look, exactly.
> tracert will tell me where routing breaks down, but if I can't resolve a
> hostname, how do I know where to place blame?
>
> Windows XP - SP2 on both desktop(home) and laptop(pro).
> The DHCP-supplied DNS is the address of the router. I suppose I could
> adjust that temporarily to the address supplied to the router, but I like
> default setups that work ;-(
>
> I've power cycled the cable modem and router, and rebooted the laptop and
> desktop. No change.
>
>
>
>
> side note: handy feature on this router. It has a redirected home page
so
> that as soon as I brought up a browser, I found myself at a router config
> page. I didn't have to put in the address of the router. When I finished
> basic config, it told me this config page wouldn't show up in the future.
>
> --
> ---
> Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5
>
Anonymous
December 13, 2004 2:34:12 PM

Archived from groups: alt.internet.wireless (More info?)

Kerry Liles wrote:
> I would recommend running services.msc from the Start|Run box and
> observing whether or not the DNS Client service is running (likely it
> is). I routinely stop that service and set it to disabled - this is
> the client side caching dns client that caches not only good dns
> replies, but also caches dns lookup failures. Caching failures may
> not be such a smart thing to do IMHO - especially if you are using
> your ISP's dns servers which may be overloaded and therefore busy and
> unresponsive.
>
You can keep the DNS Client running, and just eliminate the caching of dns
lookup failures by downloading the script file W2KWXPDNSfix.reg
http://cable-dsl.home.att.net/#dns_cache
Anonymous
December 13, 2004 2:34:13 PM

Archived from groups: alt.internet.wireless (More info?)

On Mon, 13 Dec 2004 11:34:12 -0500, "Jim Fox" <NO_foxjh_SPAM@rcn.com>
wrote:

>Kerry Liles wrote:
>> I would recommend running services.msc from the Start|Run box and
>> observing whether or not the DNS Client service is running (likely it
>> is). I routinely stop that service and set it to disabled - this is
>> the client side caching dns client that caches not only good dns
>> replies, but also caches dns lookup failures. Caching failures may
>> not be such a smart thing to do IMHO - especially if you are using
>> your ISP's dns servers which may be overloaded and therefore busy and
>> unresponsive.
>>
>You can keep the DNS Client running, and just eliminate the caching of dns
>lookup failures by downloading the script file W2KWXPDNSfix.reg
>http://cable-dsl.home.att.net/#dns_cache

Or, with XP or W2K, you can just run:
ipconfig /flushdns
I have this command setup as an icon on my desktop.

Other useful DNS incantations are:
/flushdns Purges the DNS Resolver cache.
/registerdns Refreshes all DHCP leases and re-registers DNS names
/displaydns Display the contents of the DNS Resolver Cache.
/showclassid Displays all the dhcp class IDs allowed for adapter.
/setclassid Modifies the dhcp class id.

I just love this message:
ipconfig /registerdns
Registration of the DNS resource records for all adapters of this
computer has been initiated. Any errors will be reported in the
Event Viewer in 15 minutes.

Yawn. I get to wait 15 minutes to find out what went wrong. Sigh.


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
Anonymous
December 13, 2004 3:18:53 PM

Archived from groups: alt.internet.wireless (More info?)

Thanks for posting that. Disabling the negative caching is something I knew
was possible via registry hacks; having it automated makes it somewhat
safer.



"Jim Fox" <NO_foxjh_SPAM@rcn.com> wrote in message
news:SuydnSY-Q_AcWSDcRVn-rA@rcn.net...
.....snip
> You can keep the DNS Client running, and just eliminate the caching of dns
> lookup failures by downloading the script file W2KWXPDNSfix.reg
> http://cable-dsl.home.att.net/#dns_cache
>
>
Anonymous
December 13, 2004 7:53:16 PM

Archived from groups: alt.internet.wireless (More info?)

Jim Fox <NO_foxjh_SPAM@rcn.com> wrote:
> Kerry Liles wrote:
>> I would recommend running services.msc from the Start|Run box and
>> observing whether or not the DNS Client service is running (likely it
>> is). I routinely stop that service and set it to disabled - this is
>> the client side caching dns client that caches not only good dns
>> replies, but also caches dns lookup failures. Caching failures may
>> not be such a smart thing to do IMHO - especially if you are using
>> your ISP's dns servers which may be overloaded and therefore busy and
>> unresponsive.
>>
> You can keep the DNS Client running, and just eliminate the caching of dns
> lookup failures by downloading the script file W2KWXPDNSfix.reg
> http://cable-dsl.home.att.net/#dns_cache

Winner. That would explain symptoms I've seen here and at work for a long
time. At work it happens infrequently, but I think I'll still whack it.

I still don't know how to pinpoint who is causing the errors. Since
setting the router to use a stable DNS server, I've been fine.

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5
Anonymous
December 13, 2004 8:03:29 PM

Archived from groups: alt.internet.wireless (More info?)

Airhead wrote:
> <dold@XHowXdoXIX.usenet.us.com> wrote in message
> news:cpicb6$rqs$1@blue.rahul.net...
>
>>I just installed a Netgear WGR614v4 54g router, latest firmware V5.0_02
>>pre-installed. I cloned my MAC address and connected to cable modem.
>>I had previously been running an SMC7004WFW-802.11b router against this
>>same cable modem. (The wireless in that one started dying occasionally,

Make sure that if you previously had ICS installed on the machine, that
it has been removed, otherwise the DNS requests will firstly try and get
DNS in this way, resulting in a timeout. Only after this has timed out
will the DNS servers on your router be contacted, by which time your
browser may well have timed out as well.
I had this problem on a customer's machine who was complaining of big
latency when trying to view any URL, which resulted in most pages not
being displayed, and the ones that did were VERY slow even though they
had 2Mb dsl. Removing ICS from the machine fixed the problem.

VERY slow pings are a symptom of this problem.

Hope this helps

Peter Phillips
Software Director
Kinetiq Networks Ltd (UK)
Anonymous
December 13, 2004 10:51:55 PM

Archived from groups: alt.internet.wireless (More info?)

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote:

> Or, with XP or W2K, you can just run:
> ipconfig /flushdns
> I have this command setup as an icon on my desktop.

Then I would have been a little less tired of re-running the command last
night ;-(

The closest that I can come to "troubleshooting" would be a script to drive
nslookup, checking each of several name servers. But if it's a flaky
server, that might not have pointed the finger well enough.

I've set the router to a static DNS server IP. The router in turn gives
its own address as the DNS server to my network via DHCP. It seems to work
fine today. If it fails, I presume that it will fail in solid fashion and
be a little easier to track down except that I will certainly forget that I
set the static address on that obscure router screen.

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5
!