How to increase the size of the MAC address caching table?

Alexandr Baryshnyev abb at abbon.net
Sat Jul 18 13:23:57 UTC 2020


18.07.2020 16:16, Alexander V. Chernikov пишет:
> 18.07.2020, 13:56, "Alexandr Baryshnyev" <abb at abbon.net>:
> 
>     Hello everybody.
> 
>         I have about 1,500 devices on the network, but in fact the MAC address table on the central router running Freebsd
>     12.0 never contains more than 1000 with small cached records. In the network, there are short-term random interruptions
>     between different hosts and the router. The connection to the Internet on different computers in the network is lost for
>     a short time. No apparent cause of these breaks was found.
> 
> How often does this happens and what is the average "short-term" duration?
> I'd look into route -n monitor (don't remember if arp state reporting was merged into 12.0) and try to tcpdump arp 
> traffic to get understanding what's happening here.
> Also: does this router perform TCP termination of the flows toward Internet?
> 
> 
>         There is a suspicion that the MAC address table on the FreeBSD router has a limited size, about 1000 with a small
>     record maximum. Is that so? Is it possible to increase the size of this table if it is limited? An internet search was
>     not successful.
> 
> It's not limited.
> 
> 
>        Help me, please.
> 
>       > arp -an | grep -ve incomplete | wc -l
>           1055
> 



> "Incomplete" are still entries in the per-interface mac address table. What's the size with incomplete ones?

> arp -an | wc -l
     1183
> ifconfig bridge0 addr | wc -l
     1214


> 
>        Thank you.
> 
>     --
>          Best regards,
>          Alexandr B. Baryshnyev, e-mail: abb at abbon.net <mailto:abb at abbon.net>
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-- 
    Best regards,
    Alexandr B. Baryshnyev, e-mail: abb at abbon.net


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