Weird Network Problem

Discussion in 'NZ Computing' started by Dorado, Dec 7, 2004.

  1. Dorado

    Dorado Guest

    This is the weirdest problem I have ever come across and I'm lost as to what
    the cause is.

    I have 3 machines,
    (A) - Windows 2000 SP4
    (B) - Windows Server 2003
    (C) - Windows XP SP2 (Laptop)

    All are connected to the same switch, it also has my ADSL router (which acts
    as the DHCP server). The problem is this, When I reboot and connect (C) to
    the network it can ping the other two machine fine.. for a while. After a
    while ping requests to (A) time out...

    What is weird is that (B) can still ping both the machines fine, and (C) can
    ping (B). It appears that the connection between (A) and (C) has somehow
    disappeared??? I have tried rebooting my switch assuming it was a switching
    problem in hardware but that hasn't solved it.

    The fact that this happens only after a little while has got me stumped. The
    only change done to my network was the installation of Squid 2.5 on (A),
    although I cant see how that can cause this problem?

    Any ideas as to what I can try? (I have tried disabling Squid.. hasn't
    helped)

    Cheers,
    Dorado
    Dorado, Dec 7, 2004
    #1
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  2. Dorado

    DoggNZ Guest

    On Wed, 8 Dec 2004 08:09:30 +1300, "Dorado" <>
    wrote:

    >This is the weirdest problem I have ever come across and I'm lost as to what
    >the cause is.
    >
    >I have 3 machines,
    >(A) - Windows 2000 SP4
    >(B) - Windows Server 2003
    >(C) - Windows XP SP2 (Laptop)
    >
    >All are connected to the same switch, it also has my ADSL router (which acts
    >as the DHCP server). The problem is this, When I reboot and connect (C) to
    >the network it can ping the other two machine fine.. for a while. After a
    >while ping requests to (A) time out...
    >
    >What is weird is that (B) can still ping both the machines fine, and (C) can
    >ping (B). It appears that the connection between (A) and (C) has somehow
    >disappeared??? I have tried rebooting my switch assuming it was a switching
    >problem in hardware but that hasn't solved it.
    >
    >The fact that this happens only after a little while has got me stumped. The
    >only change done to my network was the installation of Squid 2.5 on (A),
    >although I cant see how that can cause this problem?
    >
    >Any ideas as to what I can try? (I have tried disabling Squid.. hasn't
    >helped)
    >
    >Cheers,
    >Dorado
    >


    That IS weird. I suppose you've already tried the obvious things like
    a different port on your switch and different cables. I had an issue a
    while back where an XP machine would crash very occasionally when
    browsing network shares but otherwise surfed the net etc fine. Swapped
    the NIC and hasn't skipped a beat since.

    --
    BOINC SETI
    http://boinc.mundayweb.com/seti2/stats.php?userID=1469&trans=off
    DoggNZ, Dec 7, 2004
    #2
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  3. Dorado

    Dorado Guest

    DoggNZ wrote:
    > On Wed, 8 Dec 2004 08:09:30 +1300, "Dorado" <>
    > wrote:
    >
    >> This is the weirdest problem I have ever come across and I'm lost as
    >> to what the cause is.
    >>
    >> I have 3 machines,
    >> (A) - Windows 2000 SP4
    >> (B) - Windows Server 2003
    >> (C) - Windows XP SP2 (Laptop)
    >>
    >> All are connected to the same switch, it also has my ADSL router
    >> (which acts as the DHCP server). The problem is this, When I reboot
    >> and connect (C) to the network it can ping the other two machine
    >> fine.. for a while. After a while ping requests to (A) time out...
    >>
    >> What is weird is that (B) can still ping both the machines fine, and
    >> (C) can ping (B). It appears that the connection between (A) and (C)
    >> has somehow disappeared??? I have tried rebooting my switch assuming
    >> it was a switching problem in hardware but that hasn't solved it.
    >>
    >> The fact that this happens only after a little while has got me
    >> stumped. The only change done to my network was the installation of
    >> Squid 2.5 on (A), although I cant see how that can cause this
    >> problem?
    >>
    >> Any ideas as to what I can try? (I have tried disabling Squid..
    >> hasn't helped)
    >>
    >> Cheers,
    >> Dorado
    >>

    >
    > That IS weird. I suppose you've already tried the obvious things like
    > a different port on your switch and different cables. I had an issue a
    > while back where an XP machine would crash very occasionally when
    > browsing network shares but otherwise surfed the net etc fine. Swapped
    > the NIC and hasn't skipped a beat since.


    Yup have already tried changing cables and trying a different port.. same
    problem :(
    Dorado, Dec 7, 2004
    #3
  4. Dorado

    Alan Guest

    "Dorado" <> wrote in
    message news:cp4v57$rra$...
    >
    > This is the weirdest problem I have ever come across and I'm lost as
    > to what the cause is.
    >
    > I have 3 machines,
    > (A) - Windows 2000 SP4
    > (B) - Windows Server 2003
    > (C) - Windows XP SP2 (Laptop)
    >
    > All are connected to the same switch, it also has my ADSL router
    > (which acts as the DHCP server). The problem is this, When I reboot
    > and connect (C) to the network it can ping the other two machine
    > fine.. for a while. After a while ping requests to (A) time out...
    >
    > What is weird is that (B) can still ping both the machines fine, and
    > (C) can ping (B). It appears that the connection between (A) and (C)
    > has somehow disappeared??? I have tried rebooting my switch assuming
    > it was a switching problem in hardware but that hasn't solved it.
    >
    > The fact that this happens only after a little while has got me
    > stumped. The only change done to my network was the installation of
    > Squid 2.5 on (A), although I cant see how that can cause this

    problem?
    >
    > Any ideas as to what I can try? (I have tried disabling Squid..

    hasn't
    > helped)
    >
    > Cheers,
    > Dorado
    >


    Could something be overheating?

    I cannot think what it might be, but given it only happens after you
    have been going for a while makes me think something it getting hot
    perhaps?

    HTH,

    Alan.
    Alan, Dec 7, 2004
    #4
  5. Dorado

    Mark S Guest

    Very strange. Are you using the Firewall in SP2? Try disabling that.

    Are you using the same subnet for all machines?

    Recheck the IP settings for each PC when it happens, make sure the subnets
    are the same.

    Try running arp -a before and during the fault to see if its an arp issue.
    (your swtich may be faulty and corrupting the arp tables or the nic on A
    could be faulty).


    "Dorado" <> wrote in message
    news:cp51eu$um5$...
    > DoggNZ wrote:
    > > On Wed, 8 Dec 2004 08:09:30 +1300, "Dorado" <>
    > > wrote:
    > >
    > >> This is the weirdest problem I have ever come across and I'm lost as
    > >> to what the cause is.
    > >>
    > >> I have 3 machines,
    > >> (A) - Windows 2000 SP4
    > >> (B) - Windows Server 2003
    > >> (C) - Windows XP SP2 (Laptop)
    > >>
    > >> All are connected to the same switch, it also has my ADSL router
    > >> (which acts as the DHCP server). The problem is this, When I reboot
    > >> and connect (C) to the network it can ping the other two machine
    > >> fine.. for a while. After a while ping requests to (A) time out...
    > >>
    > >> What is weird is that (B) can still ping both the machines fine, and
    > >> (C) can ping (B). It appears that the connection between (A) and (C)
    > >> has somehow disappeared??? I have tried rebooting my switch assuming
    > >> it was a switching problem in hardware but that hasn't solved it.
    > >>
    > >> The fact that this happens only after a little while has got me
    > >> stumped. The only change done to my network was the installation of
    > >> Squid 2.5 on (A), although I cant see how that can cause this
    > >> problem?
    > >>
    > >> Any ideas as to what I can try? (I have tried disabling Squid..
    > >> hasn't helped)
    > >>
    > >> Cheers,
    > >> Dorado
    > >>

    > >
    > > That IS weird. I suppose you've already tried the obvious things like
    > > a different port on your switch and different cables. I had an issue a
    > > while back where an XP machine would crash very occasionally when
    > > browsing network shares but otherwise surfed the net etc fine. Swapped
    > > the NIC and hasn't skipped a beat since.

    >
    > Yup have already tried changing cables and trying a different port.. same
    > problem :(
    >
    >
    Mark S, Dec 7, 2004
    #5
  6. Dorado

    Dorado Guest

    Mark S wrote:
    > Very strange. Are you using the Firewall in SP2? Try disabling that.
    >
    > Are you using the same subnet for all machines?
    >
    > Recheck the IP settings for each PC when it happens, make sure the
    > subnets are the same.
    >
    > Try running arp -a before and during the fault to see if its an arp
    > issue. (your swtich may be faulty and corrupting the arp tables or
    > the nic on A could be faulty).
    >
    >
    > "Dorado" <> wrote in message
    > news:cp51eu$um5$...
    >> DoggNZ wrote:
    >>> On Wed, 8 Dec 2004 08:09:30 +1300, "Dorado" <>
    >>> wrote:
    >>>
    >>>> This is the weirdest problem I have ever come across and I'm lost
    >>>> as to what the cause is.
    >>>>
    >>>> I have 3 machines,
    >>>> (A) - Windows 2000 SP4
    >>>> (B) - Windows Server 2003
    >>>> (C) - Windows XP SP2 (Laptop)
    >>>>
    >>>> All are connected to the same switch, it also has my ADSL router
    >>>> (which acts as the DHCP server). The problem is this, When I reboot
    >>>> and connect (C) to the network it can ping the other two machine
    >>>> fine.. for a while. After a while ping requests to (A) time out...
    >>>>
    >>>> What is weird is that (B) can still ping both the machines fine,
    >>>> and (C) can ping (B). It appears that the connection between (A)
    >>>> and (C) has somehow disappeared??? I have tried rebooting my
    >>>> switch assuming it was a switching problem in hardware but that
    >>>> hasn't solved it.
    >>>>
    >>>> The fact that this happens only after a little while has got me
    >>>> stumped. The only change done to my network was the installation of
    >>>> Squid 2.5 on (A), although I cant see how that can cause this
    >>>> problem?
    >>>>
    >>>> Any ideas as to what I can try? (I have tried disabling Squid..
    >>>> hasn't helped)
    >>>>
    >>>> Cheers,
    >>>> Dorado
    >>>>
    >>>
    >>> That IS weird. I suppose you've already tried the obvious things
    >>> like a different port on your switch and different cables. I had an
    >>> issue a while back where an XP machine would crash very
    >>> occasionally when browsing network shares but otherwise surfed the
    >>> net etc fine. Swapped the NIC and hasn't skipped a beat since.

    >>
    >> Yup have already tried changing cables and trying a different port..
    >> same problem :(


    The firewalls were all disabled when I was testing this. The IP addresses
    are all assigned via DHCP and have the same subnets (I manually checked this
    too). I have checked arp and the MAC address assignments to the IP address
    is correct. Basically the arp tables are identical on both (B) and (C). I
    have tried this on another Windows 2000 machine (D) connected to the network
    which is able to ping (A) without any problems.

    (A) can ping all other machine except (C) and (C) can ping all other machine
    except (A) .. both (B) and (D) can ping any machine.... arrrrrrrrggg
    Dorado, Dec 7, 2004
    #6
  7. Dorado

    Dorado Guest

    Alan wrote:
    > "Dorado" <> wrote in
    > message news:cp4v57$rra$...
    >>
    >> This is the weirdest problem I have ever come across and I'm lost as
    >> to what the cause is.
    >>
    >> I have 3 machines,
    >> (A) - Windows 2000 SP4
    >> (B) - Windows Server 2003
    >> (C) - Windows XP SP2 (Laptop)
    >>
    >> All are connected to the same switch, it also has my ADSL router
    >> (which acts as the DHCP server). The problem is this, When I reboot
    >> and connect (C) to the network it can ping the other two machine
    >> fine.. for a while. After a while ping requests to (A) time out...
    >>
    >> What is weird is that (B) can still ping both the machines fine, and
    >> (C) can ping (B). It appears that the connection between (A) and (C)
    >> has somehow disappeared??? I have tried rebooting my switch assuming
    >> it was a switching problem in hardware but that hasn't solved it.
    >>
    >> The fact that this happens only after a little while has got me
    >> stumped. The only change done to my network was the installation of
    >> Squid 2.5 on (A), although I cant see how that can cause this
    >> problem?
    >>
    >> Any ideas as to what I can try? (I have tried disabling Squid..
    >> hasn't helped)
    >>
    >> Cheers,
    >> Dorado
    >>

    >
    > Could something be overheating?
    >
    > I cannot think what it might be, but given it only happens after you
    > have been going for a while makes me think something it getting hot
    > perhaps?
    >
    > HTH,
    >
    > Alan.


    unlikely its heat, since the problem appears well before the machine has had
    any chance to overheat..
    Dorado, Dec 7, 2004
    #7
  8. Dorado

    Alan Guest

    "Dorado" <> wrote in message
    news:cp5dr0$9lv$...
    >
    > unlikely its heat, since the problem appears well before the machine
    > has had any chance to overheat..
    >


    You're probably right, but what about connectors (ports, cables etc)?

    Could one of them be expanding as they warm up, enough to cause a
    connection loss at some point?

    I had a client with something similar once (it was on an old AS400 so
    we are talking a while back), where it wouldn't work properly until it
    warmed up (opposite of your problem), and eventually they put it down
    to a loose connection that came right when the heat expanded the
    components.

    Anyway, very odd situation you have there!

    Alan.
    Alan, Dec 7, 2004
    #8
  9. Dorado

    Dorado Guest

    Alan wrote:
    > "Dorado" <> wrote in message
    > news:cp5dr0$9lv$...
    >>
    >> unlikely its heat, since the problem appears well before the machine
    >> has had any chance to overheat..
    >>

    >
    > You're probably right, but what about connectors (ports, cables etc)?
    >
    > Could one of them be expanding as they warm up, enough to cause a
    > connection loss at some point?
    >
    > I had a client with something similar once (it was on an old AS400 so
    > we are talking a while back), where it wouldn't work properly until it
    > warmed up (opposite of your problem), and eventually they put it down
    > to a loose connection that came right when the heat expanded the
    > components.
    >
    > Anyway, very odd situation you have there!
    >
    > Alan.


    I have tried swapping cables and ports around but this problem only happens
    between these two machines.

    I have done some more investigations which most likely points towards a
    software problem rather than hardware. I've booted the offending laptop
    using one of my BartPE CD's. When I do this I can ping all other machines
    and the network appears to function as expected.

    So most probably it has to be something in Windows that has suddenly decided
    it doesn't want to play nice. Absolutely nothing was changed on this machine
    which makes it even weirder... Hmmm
    Dorado, Dec 7, 2004
    #9
  10. Dorado

    DoggNZ Guest

    On Wed, 8 Dec 2004 12:52:59 +1300, "Dorado" <>
    wrote:

    <snip>
    >
    >So most probably it has to be something in Windows that has suddenly decided
    >it doesn't want to play nice. Absolutely nothing was changed on this machine
    >which makes it even weirder... Hmmm
    >


    Windows didn't do an automatic update and "upgrade" the drivers for
    the NIC did it?

    --
    BOINC SETI
    http://boinc.mundayweb.com/seti2/stats.php?userID=1469&trans=off
    DoggNZ, Dec 8, 2004
    #10
  11. Dorado

    Dorado Guest

    DoggNZ wrote:
    > On Wed, 8 Dec 2004 12:52:59 +1300, "Dorado" <>
    > wrote:
    >
    > <snip>
    >>
    >> So most probably it has to be something in Windows that has suddenly
    >> decided it doesn't want to play nice. Absolutely nothing was changed
    >> on this machine which makes it even weirder... Hmmm
    >>

    >
    > Windows didn't do an automatic update and "upgrade" the drivers for
    > the NIC did it?


    nope... not that I'm aware.. it usually pops up a message if an automatic
    update has been done.. saw nothing of the sort
    Dorado, Dec 8, 2004
    #11
  12. Dorado

    E. Guest

    Dorado wrote:
    > This is the weirdest problem I have ever come across and I'm lost as to what
    > the cause is.
    > Any ideas as to what I can try? (I have tried disabling Squid.. hasn't
    > helped)
    >
    > Cheers,
    > Dorado


    Have you tried running ethereal?
    I have seen similar problems caused by faulty switches, and a netgear
    dg632 which has a problem with logging overwriting all available memory.
    What type of DSL router are you using?.
    E.
    E., Dec 8, 2004
    #12
  13. Dorado

    Steve Guest

    Dorado wrote:
    > This is the weirdest problem I have ever come across and I'm lost as to what
    > the cause is.
    >
    > I have 3 machines,
    > (A) - Windows 2000 SP4
    > (B) - Windows Server 2003
    > (C) - Windows XP SP2 (Laptop)
    >
    > All are connected to the same switch, it also has my ADSL router (which acts
    > as the DHCP server). The problem is this, When I reboot and connect (C) to
    > the network it can ping the other two machine fine.. for a while. After a
    > while ping requests to (A) time out...
    >
    > What is weird is that (B) can still ping both the machines fine, and (C) can
    > ping (B). It appears that the connection between (A) and (C) has somehow
    > disappeared??? I have tried rebooting my switch assuming it was a switching
    > problem in hardware but that hasn't solved it.
    >
    > The fact that this happens only after a little while has got me stumped. The
    > only change done to my network was the installation of Squid 2.5 on (A),
    > although I cant see how that can cause this problem?
    >
    > Any ideas as to what I can try? (I have tried disabling Squid.. hasn't
    > helped)
    >
    > Cheers,
    > Dorado
    >
    >

    Had this with a cheap switch, try the old power cycle on the switch and
    see if it helps.

    Steve
    Steve, Dec 8, 2004
    #13
  14. Dorado

    Dorado Guest

    E. wrote:
    > Dorado wrote:
    >> This is the weirdest problem I have ever come across and I'm lost as
    >> to what the cause is.
    >> Any ideas as to what I can try? (I have tried disabling Squid..
    >> hasn't helped)
    >>
    >> Cheers,
    >> Dorado

    >
    > Have you tried running ethereal?
    > I have seen similar problems caused by faulty switches, and a netgear
    > dg632 which has a problem with logging overwriting all available
    > memory. What type of DSL router are you using?.
    > E.


    The router is a D-Link DSL-500... haven't had any problems with it in the
    past... check my other replies to this thread, it appears the problem might
    be software, something weird happening in Windows..
    Dorado, Dec 8, 2004
    #14
  15. Dorado

    Dorado Guest

    Steve wrote:
    > Dorado wrote:
    >> This is the weirdest problem I have ever come across and I'm lost as
    >> to what the cause is.
    >>
    >> I have 3 machines,
    >> (A) - Windows 2000 SP4
    >> (B) - Windows Server 2003
    >> (C) - Windows XP SP2 (Laptop)
    >>
    >> All are connected to the same switch, it also has my ADSL router
    >> (which acts as the DHCP server). The problem is this, When I reboot
    >> and connect (C) to the network it can ping the other two machine
    >> fine.. for a while. After a while ping requests to (A) time out...
    >>
    >> What is weird is that (B) can still ping both the machines fine, and
    >> (C) can ping (B). It appears that the connection between (A) and (C)
    >> has somehow disappeared??? I have tried rebooting my switch assuming
    >> it was a switching problem in hardware but that hasn't solved it.
    >>
    >> The fact that this happens only after a little while has got me
    >> stumped. The only change done to my network was the installation of
    >> Squid 2.5 on (A), although I cant see how that can cause this
    >> problem?
    >>
    >> Any ideas as to what I can try? (I have tried disabling Squid..
    >> hasn't helped)
    >>
    >> Cheers,
    >> Dorado
    >>
    >>

    > Had this with a cheap switch, try the old power cycle on the switch
    > and see if it helps.
    >
    > Steve


    Have tried that.. also tried changing ports and cables.. same problem, but
    only with these two machines
    Dorado, Dec 8, 2004
    #15
  16. Dorado

    Gavin Tunney Guest

    On Wed, 8 Dec 2004 08:09:30 +1300, "Dorado" <>
    wrote:

    >This is the weirdest problem I have ever come across and I'm lost as to what
    >the cause is.
    >
    >I have 3 machines,
    >(A) - Windows 2000 SP4
    >(B) - Windows Server 2003
    >(C) - Windows XP SP2 (Laptop)
    >
    >All are connected to the same switch, it also has my ADSL router (which acts
    >as the DHCP server). The problem is this, When I reboot and connect (C) to
    >the network it can ping the other two machine fine.. for a while. After a
    >while ping requests to (A) time out...
    >
    >What is weird is that (B) can still ping both the machines fine, and (C) can
    >ping (B). It appears that the connection between (A) and (C) has somehow
    >disappeared??? I have tried rebooting my switch assuming it was a switching
    >problem in hardware but that hasn't solved it.
    >
    >The fact that this happens only after a little while has got me stumped. The
    >only change done to my network was the installation of Squid 2.5 on (A),
    >although I cant see how that can cause this problem?
    >
    >Any ideas as to what I can try? (I have tried disabling Squid.. hasn't
    >helped)
    >


    Try disabling full duplex on all the NICs.

    Cheers

    Gavin
    Gavin Tunney, Dec 9, 2004
    #16
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