Re: MTU/MRU, always-defrag, diald, masq not working for some URLs

Ben Greear (greear@cyberhighway.net)
Sat, 26 Dec 1998 18:02:22 -0700

Fuzzy Fox wrote:
>
> Tom Oehser <tom@toms.net> wrote:
> >
> > The mtu/mru 1500 causes the problem to go away.
>
> Many people find that to be the case.
>
> > Given that this is a bad wrong problematic kludge, where should I be
> > looking to fix this *without* changing my mtu/mru from 296 to 1500?
>
> It seems that most folks are able to live with the larger MTU. The fast
> speed of today's modems means that the time difference to transfer a
> 296-byte packet, vs. a 1500-byte packet is somewhere near 300 ms.
> Certainly measurable, but not like it was in the 2400-baud days.

The sanest explanation for this problem (I've hit it too) I have
heard is: The the ICMP message that is supposed to go back to
the sender to tell it that it's TU is too big is blocked or lost
during the IP Masquerading code.

For the record, I set my ethernet MTU to 552, the same as my PPP, and
that
seemed to fix things.

Now that I feel a littler braver about kernel hacking, I may try to
track
this problem down and try to squash it.

-- 
Ben Greear (greear@cyberhighway.net)  http://www.primenet.com/~greear 
Author of ScryMUD:  mud.primenet.com 4444
http://www.primenet.com/~greear/ScryMUD/scry.html


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