-On [20010808 18:51], Mike Tancsa ([EMAIL PROTECTED]) wrote:
>
>Thanks for the clarification. I just had a read of the man pages as well
>and there is mention of that too. I guess the question I am left with is
>that can I safely set the MTU to 1500 if I am using it to tunnel IPV4
>traffic only, and in another case, IPV4 and IPSEC traffic. When using 1280
>in a strict tunnel mode, I have problems with large packets from certain
>sites. Broken PMTU somewhere ? Not sure, but setting the MTU to 1500
>seemed to fix it.
What I understand is that using a MTU of 1280 guarantees no IPv6
fragmentation since it is the minimum supported.
Of course, if a link cannot accomodate the MTU it must fragment at a
layer below the IPv6 layer, but it will not be fragmented on the IPv6
layer itself.
Of course, like the RFC says:
"[...]; it is recommended that they be configured with an MTU of 1500
octets or greater, to accommodate possible encapsulations (i.e.,
tunneling) without incurring IPv6-layer fragmentation."
So it seems that the IPv6 fragmenting is causing problems of some sort.
My best guess at least. :)
--
Jeroen Ruigrok van der Werven/Asmodai asmodai@[wxs.nl|freebsd.org|xmach.org]
Documentation nutter/C-rated Coder, finger [EMAIL PROTECTED]
http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/
Teaching should be such that what is offered is perceived as a valuable
gift and not as a hard duty...
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