Subject: Re: "dribbling bit"
To: Michael Richardson <>
From: None <>
List: tech-net
Date: 01/20/2003 14:27:16
Based on the device name, I believe you may be using a NIC with the RealTek
chipset.  I have seen many different bizarre errors with these NICs, in Netbsd
as well as other operating systems.

This is easy to verify or refute; stick a different NIC in the box and see if
the problem goes away.

I ultimately removed all RealTek based NICs from my firewalls and the problems
immediately and permanently disappeard.

"Non-integer number of bytes" doesn't make sense.  There is no such thing as a
fraction of a byte.  I think they mean that there are framing errors and the
stream is interpreted as having bits that are not part of a byte.  In any event
it must be a framing error; to really see why requires a storage scope or an
old style network analyzer that shows you the serial bit stream.

On 20-Jan-2003 Michael Richardson wrote:
>>>>>> "Michael" == Michael Richardson <> writes:
>     Michael> My firewall has started to do:
>     Michael> Jan 20 10:35:20 bud /netbsd: tlp0: receive error: dribbling bit
>     Michael> Jan 20 10:35:20 bud /netbsd: tlp0: receive error: CRC error
>     Michael> Jan 20 10:35:22 bud /netbsd: tlp0: receive error: dribbling bit
>     Michael> Jan 20 10:35:22 bud /netbsd: tlp0: receive error: CRC error
>     Michael> This interface is plugged directly into a GVC ADSL modem doing
>     Michael> bridged ethernet. 
>     Michael> A couple of other interfaces did this for awhile, and the switch
> died or
>     Michael> needed to be reset soon afterwards. The GVC ADSL modem has been
> power cycled
>     Michael> already.  (As has the firewall)
>     Michael> Can anyone say what this means? Clearly, there is corruption,
> which the CRC
>     Michael> is in fact catching, but any deeper hit on the dribbling bit?
> This is a
>     Michael> D-LINK 4-port card in a Dell Optiplex (thus the two PCI
>     Michael> bridges):
>   Okay, found the datasheet... dribbling bit means that I'm getting
> non-integer number of bytes. Cables do not usually go bad suddendly. I wonder
> if something else moved too close. Any advice welcome.
> ]       ON HUMILITY: to err is human. To moo, bovine.           |  firewalls 
> [
> ]   Michael Richardson, Sandelman Software Works, Ottawa, ON    |net
> architect[
> ] |device
> driver[
> ] panic("Just another Debian GNU/Linux using, kernel hacking, security guy");
> [
> Version: GnuPG v1.0.7 (GNU/Linux)
> Comment: Finger me for keys
> iQCVAwUBPiw2OoqHRg3pndX9AQEKgQQAimuqN65FpVx51tKwgF0niKf64pNmaPyB
> TV8bzKPhonnphqyZulBiWhuotZhh0/Ojw/qxqOtFgInDbp+sdljwGZhYDEkEaV8p
> G+8ZFRzYbbNJBgQ/MxGENiKxAMffWCmfSaWA2jWDGZFr+XdiNp5QmCUm8o9E6Zzt
> jSr9ueiDkYE=

Seth Kurtzberg
M. I. S. Corp.
Date: 20-Jan-2003
Time: 14:22:00

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