[ale] Strange Linux networking issue
derek at ihtfp.com
Mon Apr 19 14:37:38 EDT 2021
On Mon, April 19, 2021 2:17 pm, Jim Kinney wrote:
> Two hosts directly connected with neither switch nor cross-over cable.
> Sounds like the two nics auto-negotiated themselves to death.
That was certainly one of my theories. (NB: I'm helping someone else
debug this, it's not my design). The strange part was that it was working
fine for a week or two before kicking the bucket.
> To test, stop networking on boxA, rmmod nic modules, insmod nic modules,
> start networking. If ping runs a bit after that, disable autoconfig.
We've been trying to do non-destructive edits at the moment to debug, but
yes, this is a good option to attempt to "get it back online".
> On April 19, 2021 1:06:07 PM EDT, Derek Atkins via Ale <ale at ale.org>
>>I'm having a strange networking issue between two AWOW devices running
>>Linux that stopped talking to each other. The devices are configured
>>--(a)[Box 1](b) ----- (c)[Box 2](d)--
>>(a) is 172.16.5.0/16
>>(b) is 172.16.5.1/16
>>(c) is 172.16.7.100/16
>>(d) is 172.16.7.0/16
>>The (b)/(c) link is a direct link between the devices, not a crossover
>>cable, and no switch.
>>The two devices were talking fine for a while and then all of a sudden
>>they stopped. Now that won't talk at all. When truing to ping .7.100
>>from Box 1, it sends out ARPs but there is no ARP response from Box 2.
>>Similarly, on Box 2 trying to ping .5.1 results in no ARP responses.
>>Both devices show the (b)/(c) link as up. Running ethtool shows the
>>is detected. However arp -an shows an incomplete response (no
>>The dmesg output doesn't show anything.
>>I am at a loss. I don't understand how or why the two devices would
>>talking, and why neither will pick it up again.
>>Any suggestions for where to look or how else to debug this?
>> Derek Atkins 617-623-3745
>> derek at ihtfp.com www.ihtfp.com
>> Computer and Internet Security Consultant
>>Ale mailing list
>>Ale at ale.org
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Derek Atkins 617-623-3745
derek at ihtfp.com www.ihtfp.com
Computer and Internet Security Consultant
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