Re: Validation of Packet Too Big Payload using Echo Request

[Timothy Winters <[e-mail]>]

On Tue, Jan 28, 2020 at 3:10 AM <[e-mail]> wrote:

> > The IPv6 Ready Logo Committee updated testing to include a test for
> validating the Packet Too Big message content based on the following part
> of 8201.
> >
> > "Nodes should appropriately validate the payload of ICMPv6 PTB
> >    messages to ensure these are received in response to transmitted
> >    traffic (i.e., a reported error condition that corresponds to an IPv6
> >    packet actually sent by the application) per [ICMPv6]."
> >
> > I've included the steps below used to verify the IPv6 implementation
> validates the Packet Too Big.
> >
> > Step
> > Action
> > Expected Behavior
> > 1.
> > TR1 forwards an Echo Request from TN2 to the NUT.  The packet size is
> 1500 octets.
> > The NUT should respond without fragmenting the packet to the Echo
> Request using TR1 as a first hop.
> > 2.
> > TR1 transmits a Packet Too Big message to the NUT with an ICMPv6
> Identifier does not match the Echo Reply in Step 1.
> >
> > 3.
> > TR1 forwards an Echo Request from TN2 to the NUT.  The packet size is
> 1500 octets.
> > The NUT should respond without fragmenting the packet to the Echo
> Request using TR1 as a first hop.
> >
> > We received a comment that this validation shouldn't apply to ICMPv6 and
> it should only apply to TCP or protocols that have state.   Do we think
> this only applies to TCP or is it valid for all traffic?
>
> RFC8201 is a network layer mechanism, and the paragraph above applies to
> all packets sent by the node. Regardless of transport layer protocol.
>
Thanks for the replies that's my opinion as well.  We'll leave it as
documented.

~Tim

>
> Best regards,
> Ole