Date: Sat, 14 Jul 2007 20:51:38 -0700 From: John-Mark Gurney <gurney_j@resnet.uoregon.edu> To: Sten Daniel Soersdal <netslists@gmail.com> Cc: Stephen.Clark@seclark.us, freebsd-net@freebsd.org Subject: Re: 6.2 mtu now limits size of incomming packet Message-ID: <20070715035138.GP1221@funkthat.com> In-Reply-To: <4698D290.5080004@gmail.com> References: <46967C5C.5040505@seclark.us> <469772DA.1000700@gmail.com> <46977741.8090301@seclark.us> <4698D290.5080004@gmail.com>
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Sten Daniel Soersdal wrote this message on Sat, Jul 14, 2007 at 15:41 +0200:
> You are trying to lower the mtu on the wrong end.
> As i said, all hosts on the same L2 needs to share the same mtu.
> The router that forwarded you that packet is obviously not using the
> same mtu (otherwise it would not be able to forward it to you).
> Either you need to lower that routers local interface mtu or you need to
> raise your hosts mtu to match that of the router.
> Because ALL hosts on the same L2 network need to have the same mtu.
I hope that this will not be the cast in the future... I have already
fixed -current to follow the host route's MTU instead of the interface's
mtu.. This means that you can modify a host's mtu by:
route change <host> -mtu <smaller mtu>
And all packets to the host will follow the smaller MTU... This means
that we can have the interface mtu set to 9000 (or larger), and change
the local network route to have an mtu of 1500 (host routes are cloned
from this), and then the mtu daemon can probe the host to see if a
larger mtu is possible, and change the route to allow the larger mtu...
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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