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Date: Tue, 28 Aug 2007 21:52:46 +0100
From: "Bruce M. Simpson" <bms@FreeBSD.org>
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To: Weiguang Shi <wgshizz@yahoo.com>
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Cc: freebsd-net@freebsd.org
Subject: Re: nc captures 1024 bytes
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Weiguang Shi wrote:
> nc might be waiting on all the interfaces; enumerating MTUs and choosing the largest
> sounds complicated, especially when some interfaces can be configured to receive 
> jumbo frames. Why not just use something like 64KB as the other user
> suggested or something even larger?
>   

That is the easy fix, yes. :^)

If the socket's pcb laddr is bound to an IP, and IP to which it is bound 
stays on the same physical interface, then the MTU may easily be 
obtained. If it's INADDR_ANY, or you expect the IP to be dynamically 
reconfigured on another interface, then auto-tuning is not possible.

regards,
BMS