On Fri, 20 Nov 1998, Greg A. Woods wrote:

> [ On Fri, November 20, 1998 at 13:58:28 (-0800), Marc Slemko wrote: ]
> > Subject: Re: SOLVED!  The cause of puzzling TCP (eg. WHOIS) connection failures  with some InterNIC.net hosts
> >
> > I thought you had said that there were no differences in the traffic
> > dumps between working and non-working connections...
> 
> I do think it would be more friendly for a NetBSD router to optionally
> ignore the "DF" bit if the same oversize packet is re-transmitted even
> after the ICMP "needs frag" reply has been sent, perhaps after "N"
> retransmissions where "N" is calculated based on some magical formula
> that uses the packet size and the delay between retransmissions in order
> to guess at how long it would take the ICMP reply to get back to the
> originator and for a smaller packet to arrive.

And how do we remember which hosts (of the 4 billion possibal on the
internet, lets not consider ipv6) we should ignore the DF bit.  How do we
know that it isn't a case of someone setting the DF bit, and then getting
disconnected (from their dynamic IP), and a different host comes online
soon after and trys to find the problem.

Perhaps I'm wrong, but this sounds to be like a potential dinial of
service attack against a router, just get the router to run out of memory
trying to remember which hosts it is ignoreing the DF bit for.  

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