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Date: Wed, 30 May 2012 18:36:10 +0700
From: Eugene Grosbein <egrosbein@rdtc.ru>
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To: Bruce Cran <bruce@cran.org.uk>
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Cc: freebsd-net@freebsd.org
Subject: Re: if_em and large mtu bug?
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30.05.2012 17:44, Bruce Cran пишет:
> Are there any known problems with if_em and jumbo packets? I've found 
> that my ssh connection breaks (when running dmesg etc.) if I configure 
> the mtu to 9216 via rc.conf - but if I initially use a 1500 byte mtu and 
> then manually configure it to 9216 then no problems occur.
> 
> I'm running the latest -current: the hardware is:
> 
> em0: <Intel(R) PRO/1000 Network Connection 7.3.2> port 0xdc00-0xdc1f mem 
> 0xfbde0000-0xfbdfffff,0xfbd00000-0xfbd7ffff,0xfbddc000-0xfbddffff irq 16 
> at device 0.0 on pci1
> em0: Using MSIX interrupts with 3 vectors

I confirm this with FreeBSD 8.2-STABLE/amd64,
em(4) 7.3.2, Intel PRO/1000 EB.

There is a workaround, though: ifconfig em0 -rxcsum -txcsum mtu 9000
work from the beginning.

Eugene Grosbein