network stalls on Fedora Core 3

[David Becker]

Keith Fetterman wrote:
> Since this problem isn't a FC3 specific problem (I also discovered the 
> same problem in the latest Ubuntu Linux), does anyone know the best 
> mailing list/forum to that discusses kernel 2.6 and ethernet driver 
> issues?  Maybe this problem has already been identified and workarounds 
> suggested.
> 
> I do know that this problem is not limited to a specific ethernet card. 

FWIW, are your ethernet cables correctly crimped? EIA/TIA 568A (or B).

If this happens with several ethernet cards with several versions of 
linux then it could be a hardware problem. I've experienced incorrectly 
crimped network cables resulting in stalls for one protocol and not 
(apparently) for others. The behaviour of the protocol may or may not 
hit deficiencies in the way the cable was crimped. This may also apply 
to different TCP/IP/Ethernet implementations.

Is the card operating at 10Mb in windows and a 100Mb in linux? 
Incorrectly crimped cables are very forgiving for 10Mb, but may stall on 
100Mb speeds. The intel driver is different from the 3com ones.

Good luck,

	David

>  I have the same problem with both an OEM 3com ethernet card and an 
> Intel ethernet card. I guess its possible they are the same chip inside 
> so they are using the same driver, but I though Intel made their own 
> network chips.
> 
> 
> 
> Tom Trebisky wrote:
> 
>> On Sat, Apr 23, 2005 at 09:27:28AM -0700, Keith Fetterman wrote:
>>
>>> Tom Trebisky wrote:
>>>
>>>> I thought I would followup post since I have been having a similar 
>>>> problem
>>>> on my home system, and MAYBE have a clue for a solution.
>>>>
>>>> ...
>>>> My home system has an intel etherpro 100 NIC, and connects through some
>>>> dogmeat ethernet switch to a Cisco 678 DSL router.  These are the 
>>>> details,
>>>> though I don't think any are particularly relevant.
>>>>
>>>> Last night I added the following entry to my /etc/sysconfig/network
>>>> file:
>>>>
>>>> IPV6_NETWORKING=no
>>>> ...
>>>> This was right after experiencing a stall using scp to copy a big
>>>> file to my home system.  After this, ... things seemed much better.
>>>
>>>
>>> I will check because you might have hit it.  One difference between 
>>> FC3, which is the 2.6 kernel, and my RHE3 systems, which is the RH 
>>> modified 2.4 kernel, might be the IPv6 settings.  In the RHE3 they 
>>> may be different or turned off by default, where as they may be 
>>> turned on by default in FC3.  I will check and retest.
>>
>>
>>
>> I am now somewhat less enthusiastic about this, although it -seemed- to
>> work.  Apparently the variable to set is:
>>
>> NETWORKING_IPV6=no (not IPV6_NETWORKING) -- I just reported verbatim what
>> some other poster advised, but a look at /etc/rc.d/init.d/network shows
>> that NETWORKING_IPV6 is the relevant variable, so it isn't clear how 
>> setting
>> IPV6_NETWORKING could do anything at all -- just a placebo ... sigh.
>>
>> And reading the posts about slow network and IPv6 issues indicate this is
>> primarily a DNS thing, not something that would slow down or stall an
>> existing TCP connection (which is what I am seeing).  see:
>>
>>     http://weblogs.mozillazine.org/darin/archives/005753.html
>>
>> To really kill ipv6 it is recommended that the following be added to
>> /etc/modprobe.conf and then REBOOT (just restarting the network won't
>> yank the ipv6 modules out of the kernel).
>>
>> alias net-pf-10 off
>> alias ipv6 off
>>
>> Then to check if ipv6 is really gone, do ifconfig -a and verify
>> that no ipv6 address is assigned to your network interface.
>>
>> This is as much as I have learned.  There definitely is something amiss
>> as far as TCP connections stalling now and then, and it really is a
>> kick in the head when it happens in the middle of editing a long email
>> like this one (knock on wood).  At first I suspected my ISP (now changed
>> for other reasons), then I suspected my wireless access point/switch
>> (now bypassed) -- but it seems to trace to fedora core 3, a fellow at
>> work reports that he is seeing similar incidents in the same timeframe
>> (i.e. as of the 2.6 kernel).  It would be better if the connection would
>> timeout and fail rather than stall and deadlock.
>>
>>     Tom
>>
> 
>