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internet drops every 5 minutes for 30 seconds then reconnects

Posted on 2009-05-20
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Last Modified: 2012-05-07
Ive had 3 IT guys look at this issue.

Our internet drops every 5 minutes for 30 seconds then reconnects.

we have replaced all networking gear and routers.
We have applied all software and firmware updates.

we have replaced all networking devices.

We have got the landlines phone lines tested and they have come back OK.

we have tested with and change service providers.

This issue happens on 3 of our pc connected to the network.

2 x desktops
2 x laptops.
wireless connections. Tried network cable and same issue.

we have sbs 2003. all clients running xp.

Any ideas?
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Question by:Cheryl Lander
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LVL 5

Expert Comment

by:AncientFrib
ID: 24430586
Is this a DSL connection?  I seem to recall a problem with one of my DSL connections dropping after a certain amount of time lapse of inactivity.  Have you looked into a "Keep-Alive" feature on the router or whichever device is making the connection with the DSL provider.  Is it PPPoE?  If so there may be some options available related to the connection.
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LVL 10

Expert Comment

by:lanboyo
ID: 24430884
As a quick troubleshooting step, download a windows version of Matt's Trace route from sourceforge...

http://winmtr.sourceforge.net/

Actual download link here

http://winmtr.sourceforge.net/winmtr_bin.zip

Unzip it to a directory, and run it. In the window select a good pingable internet site, (www.yahoo.com is nice but your choice) and let er rip.

It will send pings repeatedly to the various internet hops that allow such things.
Now wait for the problem to occur.

When it does, identify the link where the trouble starts...

Do you start to see packet loss during the issue? What is the first hop that experiences packet loss? Concentrate on these, as subsequent hops will USUALLY experience about the same level of loss, presumably due to the loss of a path to you. What percentage of packets are dropped during the outage times on these hops.

If you are getting packet loss past the first three hops, you can concentrate on your ISP. Tell them of the testing, and what you are seeing.

If it is from the first hop, you need to troubleshoot local electronics. Spanning tree or a defective device are likely.

If you never lose packets, it will be time to look at DNS.

Do you have any electric (not network) devices that share the on off patern as when you lose network connectivity?
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LVL 21

Expert Comment

by:suppsaws
ID: 24433036
Hello SWHosting,

if you attach a laptop straight to the internet line, so without the sbs, do you see the same behaviour?
if not then it is sbs related, then I need an ipconfig /all of the sbs and one client.

Regards,

suppsaws
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LVL 38

Expert Comment

by:ChiefIT
ID: 24435863
Check your duplex settings of the problem child computers. To do this, go to Device manager>>Nic Card>>advanced and look at your duplex settings.

Set them to auto negotiate.
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Author Comment

by:Cheryl Lander
ID: 24436430
ChiefIT:
The wirless card does not have settings for duplex.

Trying other solutions above now.
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LVL 38

Expert Comment

by:ChiefIT
ID: 24437044
I have MANY things that cause intermittent NIC activity. So, if no luck above, let me know.

Here are a couple more:
http://help.expedient.com/broadband/mtu_ping_test.shtml

Is IP version 6 enabled on a IPversion 4 LAN?
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Author Comment

by:Cheryl Lander
ID: 24437271
Is IP version 6 enabled on a IPversion 4 LAN?
not sure how to check this.

Did the mtu test and it came back with "packets need ot be fragmented. so following steps now.

Weird thing is ive been running this (http://winmtr.sourceforge.net/) all morning and the internet hasn't dropped once.
its like the pining is keping the connection alive.


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Expert Comment

by:AncientFrib
ID: 24440080
Which is why I think it is related to what I originally posted.  Did you check what I suggested?
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Author Comment

by:Cheryl Lander
ID: 24440370
I spoke to soon.

maybe I had a god run this morning but it does keep on dropping out.
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LVL 10

Expert Comment

by:lanboyo
ID: 24447272
Is  the sbs 2003 server running as a proxy for the network? Do your workstations need it to connect to the internet?
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Author Comment

by:Cheryl Lander
ID: 24447360
The server is connects to the router, however the server gives the pcs on the network their ip addresses.
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LVL 38

Expert Comment

by:ChiefIT
ID: 24447415
A NIC can go into a sleep mode, as sort of a power saving feature, after a period of inactivity. I think AncientFRIB is onto something, here. You might explore his thread of info.

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Author Comment

by:Cheryl Lander
ID: 24469465
Update.

It is still dying... See stats below.



|                                      WinMTR statistics                                   |

|                       Host              -   %  | Sent | Recv | Best | Avrg | Wrst | Last |

|------------------------------------------------|------|------|------|------|------|------|

|                     Network Unreachable -    8 | 2367 | 2200 |    0 |    5 |   47 |   32 |

|                     Network Unreachable -   33 | 2367 | 1592 |   15 |   38 |  125 |   31 |

|                     Network Unreachable -   33 | 2367 | 1592 |   15 |   41 |  265 |   31 |

|                     Network Unreachable -   33 | 2367 | 1591 |   15 |   48 |  297 |   31 |

|                     Network Unreachable -   33 | 2366 | 1593 |   15 |   46 |  219 |   47 |

|                     Network Unreachable -   33 | 2366 | 1592 |   15 |   44 |  187 |   47 |

|                     Network Unreachable -   33 | 2366 | 1591 |   15 |   46 |  156 |   63 |

|                     Network Unreachable -    8 | 2366 | 2178 |   15 |   38 |  156 |   47

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LVL 38

Expert Comment

by:ChiefIT
ID: 24470257
Right click My Computer >> Properties >> Hardware Tab Click Device manager>>
Expand Network Adapter >> Right click your Wireless NIC select
Properties >> Click Power Management

What options are we looking at?
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Author Comment

by:Cheryl Lander
ID: 24470274
under advanced we have a "power save mode and Its currently on nomral.

its a tp-LINK 11b/g wireless adapter.

The other one we have tested is a belkin.

ON the laptops its a intel.
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LVL 38

Expert Comment

by:ChiefIT
ID: 24470422
With a few different adapters acting a fool, do you think it could be the wireless access point, or are there other computers linked up to that wireless point?
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Author Comment

by:Cheryl Lander
ID: 24470451
There are 3 pcs / laptops linked up all with the same issue.

We purchased new routers, had the lines tested and the isp tested.
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LVL 38

Expert Comment

by:ChiefIT
ID: 24473082
What is the make/model of your Wireless Access Point?

It sounds like the cabling may be wrong or the duplex settings of the WAP may be off.
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Author Comment

by:Cheryl Lander
ID: 24477568
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Author Comment

by:Cheryl Lander
ID: 24477572
Ive also updated to the latest firmware.
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Author Comment

by:Cheryl Lander
ID: 24489169
Had an IT guy around yesterday to have a look.

hes done many tests and feels the problem is between the router and the server.

The adsl connection remains on during any drop outs.

The server is giving the pcs on the network the ip address not the router.

So I guess this is the next angle to take.
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LVL 38

Expert Comment

by:ChiefIT
ID: 24489869
OK, on the router Portfast may be disabled.

Portfast is a protocol that strips off the routing packets and sends the. The problem with portfast being disabled is newer operating systems can time out. So, you might enable portfast on the router.

I have  a difference of opinion on this article, but for the most part, it has some good information on the differences between spanning tree and portfast.

http://tcpmag.com/qanda/article.asp?editorialsid=277
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Author Comment

by:Cheryl Lander
ID: 24490050
where would this option be normally in the router.

Cant seem to find it or anything similar.
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LVL 38

Expert Comment

by:ChiefIT
ID: 24493587
Spanning tree and portfast are opposites of eachother. I am not familiar with your router. Most routers come standard with the spanning tree protocol.

Also switches have the ability to choose between spanning tree and portfast. Do you have managed switches?

Remember portfast should be enabled bewteen the computer and the port of the switch or router. However, spanning tree is good for solid connections between routers and switches.
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LVL 38

Expert Comment

by:ChiefIT
ID: 24493598
Oops, made a mistake. Most routers and switches come with portfast enabled, not spanning tree.
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Author Comment

by:Cheryl Lander
ID: 24533535
Ive got an IT guy to look at this and he cant find any reference to it.
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LVL 38

Accepted Solution

by:
ChiefIT earned 500 total points
ID: 24635223
I believe either the MTU settings or spanning tree enabled, (meaning portfast disabled), is your problem. This is enabled/disabled on the routers and switches. This will be better explained in greater deatail on a follow up thread.

I have been reviewing what we have gone over and it appears like you may be experiencing intermittent comms on your server's nic. This can happen if you have Service pack one on your server. To test for this, you can perform an MTU ping test:

Here is how to do it: (1492 is the default MTU setting, and service pack one miscoded this setting).

http://help.expedient.com/broadband/mtu_ping_test.shtml

To fix this, just download and install SP2.
____________________________________________________________
OK, remember I have helped a bunch of people with intermittent communications on their network. Well, here are a couple of them. On these thread you will see how to track down and fix intermittent connectivity:
+++++++++++++++
Multihomed server:
http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Server/2003_Server/Q_23681992.html
+++++++++++++++
Service pack 1 and the MTU settings:

(Please note this can effect any of a number of server services, like DNS or DHCP or terminal services. Also note that you don't always see any event viewer errors as in this case. Nor will the MTU settings show up on Netdiag or DCdiag reports).
http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Q_23647068.html
or
http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Server/2003_Server/Q_23306595.html
or
http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Server/2003_Server/Q_23681992.html

++++++++++++++++++++++++
IPversion 6 on a IPversion 4 network:
http://www.experts-exchange.com/Networking/Protocols/DNS/Q_23604907.html
++++++++++++++++++++++++

Portfast problem where Operating systems newer than 2000 server/pro will drop periodically:
http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Server/Windows_2003_Active_Directory/Q_23147843.html

You can enable portfast on your switches and routers:
A little explaination of spanning tree and portfast.
http://itt.theintegrity.net/pmwiki.php?n=ITT.Spanning-TreeAndPortfast
(NOTE: Portfast is necessary for XP clients. XP clients will time out otherwise.)
++++++++++++++++++++++++++++
NIC teaming and Network Load Balancing:

http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Server/2003_Server/Q_23019010.html

Network load balancing on a switched network:
NLB over a swtiched network, Microsoft Fix:
http://support.microsoft.com/kb/261957


0
 

Author Comment

by:Cheryl Lander
ID: 24635315
ok I will try all of this and award you the full points.

I think this is a real mystery.

And ive noticed over the last week it seems to get worse when it rains.

Weird,

Thank you so much for you help.
0
 

Author Closing Comment

by:Cheryl Lander
ID: 31583457
Seemed to be caused by rain. weird. Had a great run for  a week, then bad again.
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