[TriLUG] Wierd Network Problem - Clues Appreciated

Sat Nov 30 13:26:52 EST 2002

I would say just the opposite. I've had much better performance from
3coms than from the Intel nics I've used. My two cents.

 Russ

Russell A. Nelson, CISSP, CCDP, CCNP, CCDA, CCNA, MCSE
Senior Data Architect/Lead Network Engineer
Trinnix, LLC.
Office:    919.367.9915
Cell:        919.412.6111
Email:    ranelson at trinnix.com

-----Original Message-----
From: trilug-admin at trilug.org [mailto:trilug-admin at trilug.org] On Behalf
Of Jason Tower
Sent: Saturday, November 30, 2002 1:25 PM
To: trilug at trilug.org
Subject: Re: [TriLUG] Wierd Network Problem - Clues Appreciated

if you're going to spend a little extra on a "good" NIC i respectfully
suggest 
going with intels instead of 3Coms.  i've dealt with a LOT of NICs, and
i can 
say safely say that intels just seem to work better under both windows
and 
linux, and don't barf when connecting to some brands of ethernet
switches.

jason

On Saturday 30 November 2002 00:54, Scott Chilcote wrote:
> Hi,
>
> In case anyone's wondering, the problem here turned out to be a NIC
gone
> bad after all.  What threw me off was that the card I had swapped it
> with for testing had problems of its own.  They seemed similar enough
at
> the time, which started me down the wrong path.
>
> I learned a couple of useful lessons while troubleshooting this
problem:
>
> 1. Don't buy a $10 NIC from SmartLink (Davicom) as a replacement. It
> lists "Linux" as a compatible OS on the carton, but this turns out to
be
> true only if you use the source code module they provide for 2.4.X
> kernels.  My 2.4.7 kernel refused to load it, with a screenful of
> unresolved symbols.  I tried using an existing module for the card
> instead, and noticed that my SCSI hard disks were reporting timeouts
> when I used insmod to install the module.  Turns out it crapped all
over
> my boot partitions (RAID-0 setup).  Not the sort of thing I usually
> expect when trying to add a network card... Fortunately, half a day's
> work later, things are just about back to normal.  I'm going to pay
the
> extra for a 3c905b/c from now on.
>
> 2. Intrex in Cary told me repeatedly that they no longer support
Linux.
>   I'd made the mistake of asking whether they knew which of their
> network cards were supported under Linux.  I told the guy I didn't
need
> any hand holding, but he sure wanted to make the point.  Not sure why
I
> got the scalded cat response.
>
> Thanks for all the suggestions and offers of help!
>
>            Scott C.
>
> Scott Chilcote wrote:
> > Hi Folks,
> >
> > One of the systems on my LAN started dropping packets really bad
when I
> > tried communicating with machines out on the internet.  Pinging
sites
> > like yahoo and ibiblio would return 3 out of 7,  2 out of 10, etc.
and
> > TCP connections (email, web) just timed out.
> >
> > I tried two other machines on the same LAN, and they had no problems
> > communicating with systems on the internet.  This seemed to rule out
the
> > broadband router and DSL modem.
> >
> > The next thing I tried was replacing the NIC and the ethernet cable
on
> > the problem machine.  This turned out to make no improvement.  Then
it
> > occurred to me to try pinging other systems on the LAN with this
one,
> > and that worked just fine.  I put the old NIC back in, and it still
> > worked fine.  It's only getting out to the internet with this system
> > that isn't working.  I even tried it with a webserver running on a
local
> > system, and the web page came up fine.
> >
> > I then started wondering if there was a problem with one of the
ethernet
> > connections on the DSL/Router/Switch or one of the other switches,
so I
> > tried changing those around.  This made no difference.
> >
> > I've more or less ruled out an OS or configuration problem on this
> > machine, too.  It's a dual-boot system with Win98se on one
partition.
> > The behavior is identical under Win98se.  There have been no recent
> > configuration changes to this system other than adding a USB
connected
> > UPS.  I haven't tried removing that, but I guess it's worth doing.
> >
> > Another symptom happens when I try to bring up the SMC DSL Router's
> > administration web page.  The other systems can bring this page up
> > instantly.  The "problem" system takes forever to bring it up, and
it
> > draws in a tiny piece at a time.  It did this even after I swapped
out
> > the NIC and the ethernet cable.  This happens even though pings sent
to
> > this LAN address return just fine.  This sort of indicates a TCP
problem.
> >
> > Has anyone seen this kind of behavior, or can you suggest something
else
> > to try?  I'm guessing there's something wierd going on inside the
> > hardware of the faulty system, or there's a bizarre problem with the
DSL
> > router that makes it single out this one machine.  I hate to blow
$100
> > on a replacement DSL router if it isn't actually bad.
> >
> > Thanks for any help!
> >
> >                            Scott C.
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > _______________________________________________
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>
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