Hi Fernando, > -----Original Message----- > From: Fernando Gont [mailto:fgont@xxxxxxxxxxxxxxx] > Sent: Friday, October 11, 2013 1:36 AM > To: Ray Hunter; Templin, Fred L; brian.e.carpenter@xxxxxxxxx > Cc: 6man Mailing List; ietf@xxxxxxxx > Subject: Re: Last Call: <draft-ietf-6man-oversized-header-chain-08.txt> > (Implications of Oversized IPv6 Header Chains) to Proposed Standard > > On 10/11/2013 04:48 AM, Ray Hunter wrote: > > > > I think the draft does what it can in a pragmatic manner, but might > > benefit from some acknowledgement that this security approach of > > applying parsing at a single perimeter can never ever catch all > variants > > of transporting FOO over BAR. > > FWIW, my idea of the I-D is that it says "look, if you don't put all > this info into the first fragment, it's extremely likely that your > packets will be dropped". That doesn't mean that a middle-box may want > to look further. But looking further might imply > reassemble-inspect-and-refragment... or even reassemble the TCP stream > (e.g. think about a SSL/TCP-based VPN...) We definitely don't want that. That is why we would prefer for the entire header chain (starting from the outermost IP header up to and including the headers inserted by the original host) to fit within the first fragment even if there are multiple encapsulations on the path. Thanks - Fred fred.l.templin@xxxxxxxxxx > Cheers, > -- > Fernando Gont > SI6 Networks > e-mail: fgont@xxxxxxxxxxxxxxx > PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492 > > >