[CentOS] CentOS based router dropping connections

Tue Jul 24 07:23:57 UTC 2007
Chris Geldenhuis <cgeldenhuis at jhb.ullmanns.co.za>

Jesse Cantara wrote:
> Actually, I spoke too soon.
>
> Setting the NIC to 100 Mbit did not fix the issue, I just happened to 
> misdiagnose a fix, because it seemed to be working for quite some 
> time, but it is back to the old problems.
>
> Basically, I'm at wits end right now. I'm going to go down to the 
> colocation and see if they can test the network drop into our cabinet. 
> If it's not that, then I'm convinced it's the tg3 driver.
>
> -Jesse
>
> Jesse Cantara wrote:
>> The problem ended up being the "tg3" Broadcom NIC kernel module 
>> driver. It doesn't work properly at Gigabit speeds. Turning it down 
>> to 100 Megabit fixed the issue. Does anybody know where I should 
>> report this bug?
>>
>> Thanks for all your help,
>> -Jesse
>>
>> William L. Maltby wrote:
>>> On Fri, 2007-07-20 at 12:29 -0400, Jesse Cantara wrote:
>>>> Hi Bob,
>>>>
>>>> <snip>
>>>
>>>> The issue I'm having is that external traffic is being forwarded 
>>>> properly, BUT that it drops the connection occasionally. It's not 
>>>> consistent (maybe 2 out of 5 downloads from the internet through 
>>>> the router to the webserver will drop), and the connections are 
>>>> being made, so it's not a fundamental configuration issue. It's 
>>>> something more sneaky. I'm thinking that there's something in the 
>>>> kernel or network driver that isn't functioning properly, or maybe 
>>>> a buffer that is becoming full and abandoning the connection?
>>>>
>>>> <snip>
>>>
>>>> -Jesse
>>>>
>>>> Bob Chiodini wrote:
>>>>>
>>>>> Jesse Cantara wrote:
>>>>>> Hello,
>>>>>>
>>>>>> I am trying to figure out a problem I'm having using CentOS on a 
>>>>>> machine as a router. The short story is: any traffic routed 
>>>>>> through the router seems to get disconnected at random occasionally.
>>>>>>
>>>>>> <snip>
>>>
>>> Someone recently posted a thread about a similar complaint to the lists
>>> recently. IIRC, the [SOLVED] post mentioned a problem with MTU being
>>> smaller than some of the packets received at one point, causing
>>> fragmentation, and the next step not being to reassemble the packet
>>> because of a certain flag being set.
>>>
>>> I don't remember which bit the flag was and no little about this, but I
>>> remember the general gist.
>>>
>>> Maybe your problem is similar?
>>>
>>> HTH
>>> -- 
>>> Bill
>>>
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>>
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Hi Jesse,

FWIW I have an IBM346 server at a client running RHEL4 using the 
Broadcom NICS and the tg3 driver and have not experienced any dropped 
packages over the past 18 months.

ChrisG