nanog mailing list archives

Re: Maybe I'm misreading this but...


From: shields () crosslink net (Michael Shields)
Date: 17 Oct 1998 06:38:32 +0000

In article <Pine.BSF.4.02A.9810161946280.293-100000@localhost>,
Marc Slemko <marcs () znep com> wrote:
Note that if there is no MTU change at that point, there is no problem
because there will never (well, almost never and the almost is dependent
on having funky/broken routers) be any reason to be unable to fragment at
that hop.

For this to be ok, you also have to be certain that whenever you add
an interface to that router -- by adding a card, configuring a tunnel,
or anything -- that you stop and check whether you need to renumber
the 1918-using interfaces.  For a dialup box, you also need to be sure
it will never create a PPP session with an MTU unequal to the MTU of
all the other interfaces.  These things are possible, but it's more
likely that PMTU will be broken because no one will think about it
when adding an interface.
-- 
Shields, CrossLink.


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