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luvheart

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Intermittent Network Loss

There are several users experiencing this same problem just over the last month or so.  They are all running on Thinkpad T40 with the same NIC (Intel Pro/1000 MT).  The users are experiencing intermittent network connectivity losses which in turns hinders the receipt of emails.  Seems like the delay is approximately 5-10 minutes difference from their receipt of mesages on their Blackberry.  I have noticed the Event Error 40961 in the logs even prior to the NIC driver upgrade.  Mind you all other PCs are on the same network is operating fine.  

Trobleshooting Attempts:
- updated the NIC drivers which some claim to have improved the situation but the NIC is still not as
  responsive.
- swapped out network cables

Attached is the screen shot of the Event Error.
Event-ID-40961.bmp
SOLUTION
Avatar of Bjarte Fjelland
Bjarte Fjelland
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Avatar of Philonator
Couple of comments:
-Comparing Blackberry and Outlook (whichever email program) is not a fair comparison other than, "I got it on one and not the other"  5-10 minute differences are normal.
-Are these laptops connecting through Ethernet or wireless?
-Do you think you have a security authentication issue or a physical hardware connection issue?

From what I know so far, I think your switch is dying or you have a routing that is incorrect.  Have you tried any continuous ping tests or line tests?  What does the Internet do when they get this 5-10 shutdowns?

To do a ping test:

(assuming your router will let you) From one of the computers that is having the problem (xp) instructions-
start-run, then type cmd and hit enter
a black box will appear.   In that box type "ping yahoo.com -t" and hit enter
This will start to ping yahoo continuously.  If it returns "reply from....."  great leave it and let it go for a while or all day.  When you are ready to get the results hit CTRL C and it will post the statistics.  Copy it down and report back here.

If it immediately goes into "request timed out" your router will not let ping requests go through.  Don't worry about this, just abort the test.
Avatar of luvheart
luvheart

ASKER

I tried resetting the TCP/IP and still no luck.  I will try pinging next.  Stay tuned for my update.
Please view below:

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

P:\>ping www.yahoo.com -t

Pinging www.yahoo-ht3.akadns.net [209.191.93.52] with 32 bytes of data:

Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
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Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=48ms TTL=52
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Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
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Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
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Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
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Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
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Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
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Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
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Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
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Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=47ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=48ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Destination host unreachable.
Destination host unreachable.
Destination host unreachable.
Destination host unreachable.
Reply from 209.191.93.52: bytes=32 time=47ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=47ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
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Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
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Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=45ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52
Reply from 209.191.93.52: bytes=32 time=46ms TTL=52

Ping statistics for 209.191.93.52:
    Packets: Sent = 243, Received = 239, Lost = 4 (1% loss),
Approximate round trip times in milli-seconds:
    Minimum = 45ms, Maximum = 48ms, Average = 45ms
Control-C
45ms is a great ping time.  The 4 Destination host unreachable packets are what you are describing.  I would look upstream to a router or switch.  I have had this happen on a few switches where it would just cut out every 5-10 minutes.  In all cases the entire switch eventually died.  Any chance it is a netgear?

Try moving the cable that hooks in the the switch to a different port.  Take note of it.  If it fixes the problem then take a sharpie and mark the port on the switch so no one plugs into it again later (or use a piece of tape)  If the problem still persists report your findings back and we will go from there.
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Problem resolved.