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

Fuzzy Fox (fox@dallas.net)
Sat, 26 Dec 1998 01:10:31 -0600


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.

> Is there a problem with the defrag, where an interaction with diald
> between the sl0 and ppp0 causes the always-defrag to not defrag?

Many people see this without diald in the equation, so I believe it is a
problem in the IP refragmentation code, but I don't think anyone is
actively trying to solve this problem.

> Changing my MTU/MRU from 296 to 1500 causes many other problems, I
> have to find another approach to this...

Performance might be degraded, but is it that much? Is there some way
to work around it using TOS settings of ipchains?

-- 
   fox@dallas.net (Fuzzy Fox)      || "Nothing takes the taste out of peanut
sometimes known as David DeSimone  ||  butter quite like unrequited love."
  http://www.dallas.net/~fox/      ||                       -- Charlie Brown

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