help - troubleshooting network connection, possible replacement controller card

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This afternoon I booted up my desktop, but it would not connect to the
internet.  I think the problem is with the mobo (Asus A4M89GTD PrO/USB

I have the AT&T 2Wire Residential Gateway router for use with U Verse.
My o/s is Win XP 3, SP3 fully patched.  Everything was working fine
yesterday.  Today the system reports a failed connection, but the
troubleshooting wizard reports everything fine.  The icons shown in
Hardware Device Manager look OK (no yellow highlights or question

First test was to restart my desktop as a check.  Same problem.

Next, using CLI, I succesfully pinged localhost and  However,
I received "unable to reach" messages when I pinged my ISP's DNS server

My last test was to hook up my laptop to the Gateway device.  I had no
problem pinging either localhost, or

Therefore, I conclude the problem is on the desktop mobo.

Is there anything else I should check?  Is there any reasonable chance
that the problem is not hardware failure on my mobo.

If it is reasonable to assume that the problem is the hardware on my
mobo, will buying a controller card provide a workaround for my problem
(internet access by way of the AT&T Residential Gateway router).

If so, are there any brands that work well or conversely are there any
brands that should be avoided?  My experience with TrendNet, for
example, makes me want to avoid them.

Is there anything particular I should look for in the features listed
for a controller card - either as desirable or to be avoided?



Re: help - troubleshooting network connection, possible replacement controller card

On 05/29/2013 05:48 PM, John wrote:
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Is your net card even listed?

Re: help - troubleshooting network connection, possible replacement controller card

philo  wrote:
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The M4A89GTD Pro/USB3 has a RealTek 8111E, and you'd be looking
for that in Device Manager.

You can disable the NIC, in the BIOS. But it would be reasonably
difficult to do that by accident.


Re: help - troubleshooting network connection, possible replacement controller card

Paul wrote:

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If by NIC, you refer to what the BIOS describes as "Onboard LAN", it is
enabled in the BiOS.  There is a sub-category line titled "Onboard LAN
Boot ROM" that is toggled Disabled in the BIOS.  I have not touched
either setting in the BIOS and could not tell you if or when those two
settings may have been changed.

wrt the RealTek, my network icon displays the warning that there is a
connectivity problem and clicking on the icon pops open the "local
connection status" window from which I can look at properties which
opens up info about the RealTek device.  It reports the device is
working properly.  Its titled "RealTek PCIe GBE Family Controller".  It
is what I was referring to before when I said all the icons looked to
be OK.

Re: help - troubleshooting network connection, possible replacement controller card

John wrote:
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The Boot ROM is just for booting, at BIOS time. Computers can netboot
from a server, if a server is present. If you were to enable that,
and no other boot sources were available, you'd see attempts to use
PXE to reach a boot server of some sort, on the LAN. Most home users
aren't set up to do things like that.

Pinging localhost or doesn't go near the NIC. That takes
a shortcut path in the protocol stack, which avoids hardware altogether.
Working with is a good test, as that sends real packets.

These are a few things I might try. In addition to running a packet
sniffer at the same time (WireShark). Using the packet sniffer helps,
if you're debugging a complex protocol, less so for simple tests
like this.

ipconfig              <--- would tell you about current addresses
                            The Default Gateway, might be your router
                            at . If you see 169.254.x.x for
                            your IP address, that means the machine cannot
                            reach a DHCP server (your router box).

nslookup   <--- test that DNS works

ping     <--- use the numeric address you just got from
                             nslookup, and try ICMP Ping off that server.
                             Some servers have ICMP disabled, which is
                             why the ping is not answered. It's generally
                             a good sign if the ping works (hardware test).
                             This server answers pings. My response time
                             was 100 milliseconds in this case.

If the NIC connector has LEDs, you can check those to see if the port
is responding or not. Sometimes the LEDs light a particular way, according
to whether 10BT, 100BT, or 1000BT was negotiated. Really cheap motherboards,
don't put LEDS on the Ethernet connector stack (I have a $65 motherboard
like that).

If you had a Marvell brand NIC, those have a continuity check you can
run. I have a machine here, where at the BIOS level, the Marvell can
check whether the four Ethernet pairs are properly terminated, open circuit,
or short-circuited. Which is a handy feature. My first Marvell-equipped
motherboard, it was able to tell me a pin on the motherboard connector
was dirty (open circuit). Simply inserting the connector five times,
cleaned the connector and made the problem go away permanently. It
was manufacturing dirt (perhaps from when the motherboard was washed
after soldering).

Your web browser can announce a connectivity problem, if you're running
https versus http URLs, and that would be due to a security protocol
not being enabled somewhere. So not all connectivity problems, have
their roots in hardware.

If buying a NIC, I like Intel NIC chips, or Marvell. Broadcom are OK,
but you don't typically find them on add-in cards. A lot of the stuff
you're find at the local computer store, will be cheap stuff. That
stuff may work, but may use more CPU cycles than it should.

Example of an Intel card.

The only reason for wanting a quality card, is so it has some
enduring value, and doesn't immediately go into the landfill.


Re: help - troubleshooting network connection, possible replacement controller card

major editing done

Paul wrote:

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on my desktop,
ipconfig returned  
"connection-specific DNS suffix.:"  --blank--
"autoconfiguration IP Address ..."
nslookup returned
"can't find server name for address  No response from
can't find server name for address  No response from server
default servers are not available
server:  unknown
*** unknown can't find  No response from server"

the addresses in the response above are (were?) the ones provided by my
ISP.  I will wade through their site to determine if those are still
valid.  They were in use yesterday as far as I know.

as a comparison, I entered the same commands on my laptop and got much
different results:
ipconfig returned
        Connection-specific DNS Suffix  . :
        IP Address. . . . . . . . . . . . :
        Subnet Mask . . . . . . . . . . . :
        Default Gateway . . . . . . . . . :

nslookup returned
Server:  homeportal

Non-authoritative answer:

Re: help - troubleshooting network connection, possible replacement controller card

philo wrote:

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Sorry, I don't understand the question.  I am familiar enough with my
desktop O/S to find the event logs, use Windows Task Manager to monitor
processes and use CLI for basic stuff but have not dug deeper into
things so long as they worked.  If you indicate the command I need to
enter for that info, I can do so.

I have had this set up in operation for three plus months now.  As far
as I know, I have not made any changes to my internet operation.  The
most recent change I made to my desktop was upgrading the RAM about a
month ago in anticipation of changing to a 64-bit O/S sometime in the

When I switched to the U Verse equipment (router - about three months
ago), the tech who handled the wiring installed the router at the same
time.  So I have had internet access until today.

I also noticed that when things work properly, there are two solidly
lit green lights on one end, one green light on the other and one
blinking light in the middle.  The blinking light was not blinking wrt
the desktop.  It would start blinking when I connected and booted my
laptop.  It is my understanding that the blinking green light is
indicative of the connection between my router and the ISP.

Re: help - troubleshooting network connection, possible replacement controller card

On 05/30/2013 02:17 AM, John wrote:
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Ok, you said you saw no conflicts in "device manager"

However is there even a listing for your network card.

Re: help - troubleshooting network connection, possible replacement controller card

philo wrote:

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Yes.  It does.  It is reported as "the device is working properly".

The "local area connection" icon in my Windows toolbar (bottom right
hand area) has the yellow warning with the message "limited or no
connectivity" speed 10.0 Mbps.

I have internet access via my laptop using the AT&T Gateway router.
Using the ipconfig command, I noticed the results are different.

ipconfig on my desktop returns:
        Connection-specific DNS Suffix  . :  
        IP Address. . . . . . . . . . . . :
        Subnet Mask . . . . . . . . . . . :
        Default Gateway . . . . . . . . . :  

ipconfig on my laptop returns:
        Connection-specific DNS Suffix  . :
        IP Address. . . . . . . . . . . . :
        Subnet Mask . . . . . . . . . . . :
        Default Gateway . . . . . . . . . :

Re: help - troubleshooting network connection, possible replacement controller card

John wrote:
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Good, so there is the APIPA address, indicating your
computer is not able to do working DHCP with the 2wire box.

You could try pinging the 2wire box at, using
the bad NIC interface (since the laptop test, has given away
the gateway address for us). That's to prove the wiring to
the 2wire is working. I don't think the APIPA address is intended
to stop a ping from working.

You could also try a different port on the 2wire, if it has more
than one LAN connector.

This thread works through a winsock error, but you don't have
any matching error message. Apparently this is enough to stop DHCP.


Re: help - troubleshooting network connection, possible replacement controller card

Paul wrote:

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I ran the command netsh winsock reset on my desktop before trying
anything else.  It did not work.

My router has four LAN port connectors on back.  I tried my cable for
each one, but there no success.  I tried same on two of the ports with
the cable from my laptop, and it recognized the laptop connection.
pinging from the desktop generated "destination host
unreachable".  Doing the same on my laptop did reach that address.

Considering what we've done so far, I'm inclined to attribute my
problem to mechanical failure on the mobo, but I don't know if that is
throwing in the towel yet or not.  What gives me pause is that my
software reports that the RealTek device is working properly, which
suggests to me that the problem might not be hardware after all.  A
relief to me is that there appears to be no hardware failure of the
AT&T router itself.

In the back of my mind, I wonder if some TCP/IP settings got corrupted
or if I'm missing something AT&T may have done with their IP addresses.
I can't but help look at how very different the ipconfig results are
between my desktop and my laptop.  I have the AT&T router and use wire
(not wireless) to connect the router to my desktop 24/7 and to my
laptop when needed, and I was peacefully surfing the net before I
turned off my desktop for the night.

What annoys me about AT&T is that when they delivered and installed the
router, they did not provide a user/instruction manual, and they expect
you to go to their web site.  I really like hard copy manuals because
they do not require access to the Internet.  I was also a bit miffed
because as far as I can tell you have to go to their web site in order
to change settings etc on the router.  All the previous routers I had
used the browser to access and change settings but could be done
directly to the router.

I'm going to traipse through AT&T's web site to see if I can dig up any
clues about what to do next.

Re: help - troubleshooting network connection, possible replacement controller card

John wrote:
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The IP address assignment in this case, is between the computer and
the 2wire box.

There are two layers of DHCP, ISP_DHCP gives address to 2wire (public
IP address). 2wire_DHCP gives address to computer (private address
range 192.168.x.x or 10.x.x.x type address). And any sites you contact
from your computer, are "stamped" with the public_IP address. The
router in the 2wire, does NAT to translate the packet public address,
back to something on the private side of the picture. (Explanation
will be different, in an IPV6 setup...)

        ISP ------------ 2 wire
      (DHCP)                \             
                           (DHCP) ----------------- computer

Nothing between the ISP and 2wire, should be influencing the behavior
on the right hand side. The right hand side behaves, just like
a router would behave with no WAN connection. This should still
be able to get a non-APIPA address, like the type value.
Getting an APIPA address value 169.254.x.x, means the computer
on the right, isn't contacting the router at all.

                    X ----- router
                               \                    (LAN)
                              (DHCP) ---------------computer

This could be explained by a bad LAN cable. It could be
explained by an I/O on the PHY being blown out by induced
lightning. If lightning strikes within a couple hundred
feet of your location, there can be enough induced
energy, to blow out the Ethernet chip. Just the I/O pad
gets damaged, and the rest of the chip sails merrily along.

Ethernet is transformer isolated. It's really one of the nicest
imaginable schemes for networking, due to the level of
isolation and avoidance of ground loop problems. But once
the voltage rises above a couple thousand volts on the
wire in the middle, it's possible for energy to be
pumped into the LAN chip on either end. You do hear
of people occasionally losing NIC chips, after lightning.

                 Device A   ---X X------------------X X--- Device B
                              Transformer     Transformer
                              Isolation       Isolation

The Marvell brand NIC, with the diagnostic capability,
it can verify the impedance of the cable, proving things
up to the termination resistors next to Device A
is working. But it can't prove the I/O signals on the
NIC PHY interface are working. And that's the part that
occasionally gets blown out. And the thing is, if the
NIC PHY signals blow out, there is no evidence on
the computer side, that it has happened. In fact,
the symptoms (APIPA address, good Device Manager entry)
are consistent with such a failure. All that's missing
in your case, is a plausible explanation of how it happened.

On your motherboard, the transformers can be housed in
a black chip-like thing, next to the Ethernet stack connector.
Or, in some cases, the signal transformers are inside the stack

There have been NIC chips, that spontaneously blow up, like
some Attansic ones. (Some Asus motherboards had a high
dropout rate on the NIC, losing Ethernet in the first month
of usage.) But that isn't too common, otherwise.


Re: help - troubleshooting network connection, possible replacement controller card

Paul wrote:

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Sigh.  From what we've discussed so far, it looks like I should plan to
buy a NIC card.  That's what I expected when I initially posted, just a
shame to see it confirmed.  I'll probably go down the cheap path
because I'm not prepared to spend substantial amounts at present
despite how cool that Marvell card sounds  :-)

My Asus board is almost two years old now, so I'll check to see if it
still is under warranty.  That may be a possibility though I won't plan
on that.  The lightning issue is always something that could happen
around here, though I don't recall any lightning activity the night
before.  There had been some the day before, but IIRC my computer was
turned off.  A UPS has actually been on my shopping list, but I'm
keeping an eye out for a sale at NewEgg that would fit power-wise with
my equipment.

This exercise reminds me why I bought quality server mobos before
rather than consumer boards.  It seemed reasonable to me to buy a basic
mobo and add on cards tailored to my interests (soundcards and video
cards then) rather than go for bells and whistles.



Re: help - troubleshooting network connection, possible replacement controller card

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I'd try changing the ethernet cable and a different port in the router
first if you didn't already. At least the cable and port you used with
your laptop should be known good now.

Then there's always the chance it's a software problem. I had this weird
issue in my work laptop where ethernet would just quit in the afternoon
at some point but would come back after a reboot or the Windows 7
"repair" option which basically resets the network card. Ended up having
IT upgrade the thing to 64-bit Windows 7 frin of 32-bit since I was
short on RAM too.

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Yes. External USB to ethernet ones are easy to install too. During my
ethernet problem I used some cheapie USB ethernet adapter that I had

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Intel's traditionally good. In fact I've been thinking about getting one
of their cards for my desktop since the motherboard's Broadcom chip
really likes to take its time starting up. Nothing dumber than having a
fast PC that boots up fast but then you don't have network going because
Mr. Broadcom is still twiddling his thubms or whatever...

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Not really, basically anything should work.

Re: help - troubleshooting network connection, possible replacement controller card

On 5/29/2013 6:48 PM, John wrote:
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Before looking for more difficult and possibly more expensive hoops to jump  
through, try changing the network cable between the computer and the gateway.

Flollow-up Re: help - troubleshooting network connection

Just to let all of you who posted that, after all the effort, my
desktop has resumed connecting.  Just before I was about to leave to go
to one of the local stores looking for a NIC card.

I tried one last thing - pulling the plug on the router and
disconnecting the power to my desktop and letting them sit awhile.
After plugging them both back into the electrical outlets, my desktop
finally connected to the router.  Long live Murphy, right?

So I'll keep an eye out for a good price on a NIC card when NewEgg puts
them on sale again and probably buy one to keep on hand as a precaution.

Thanks for everyone's help.  I learned a few things about networks and
routers - actually more than I will probably remember because this
problem just doesn't happen often enough and I can hope at least that
it won't repeat itself.


Re: Flollow-up Re: help - troubleshooting network connection

On 5/31/2013 5:46 PM, Yes wrote:
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Power cycling a router is often a way to fix unexplainable problems. My  
router works perfectly except that, every several months, my Nexus S phone  
suddenly becomes unable to connect. Every wired device and my notebook  
which connects wirelessly are fine but cycling the router is the only way  
to get the phone to connect. I've just gotten to accept is as one of the  
mysteries of the universe...

Re: help - troubleshooting network connection, possible replacement controller card

My guess is that you will eventually have the same problem reappear.

In my service work I've run across several cases where routers have
failed to provide addresses to local machines, not that there is a
problem with the router or local machine, but the two just don't work
together. Favorite one was where it started with one PC and over about 2
years had failed on every one.  Solution, when I finally got tired of
dealing with it, was to manually set IP addresses.  Router would do
everything it needed to do, computers did everything they were expected
to do, but the computer ended up with the built in 169. failed address.
Different computer on the port might work, different router might work
with the computer, but once the two started failing together it was over
within days.

Have also run across the issues with other networking. It can lead to
some real headbanging until it is sorted out.


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