Re: [tsvwg] UDP Options: on forcing the use of UDP CS=0 in connection with FRAG+LITE

[[e-mail]]

Dropping a packet with zero checksum to prevent possible port pollution of another service due to misdelivery (which a checksum would have caught) is, to my mind, the best action possible.
The checksum is a proof-of-work minimum criterion; you don't do the work on the checksum, I don't do the work to carry you across my network.
RFC6935 was written from the perspective of tunnelers who benefit, not from the perspective of the network as a whole. We speak not for the factory, but for the trees. Prevent pollution.
Lloyd [e-mail]

On Tuesday, July 2, 2019, 2:47 pm, Tom Herbert <[e-mail]> wrote:

On Mon, Jul 1, 2019 at 8:40 PM Joe Touch <[e-mail]> wrote:
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> On Jul 1, 2019, at 8:00 PM, Tom Herbert <[e-mail]> wrote:
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>> Yes. I find it ironic that you care so much to ensure that the checksum validates addresses and ports that nats change and here you’ve found a true error that you want to cover up instead of fix.
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> What is the "true error" to which you're referring?
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> Intermediate devices dropping cs=0.
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Section 4.3 of RFC6935 is pertinent:

"Applicability Statement for the Use of IPv6 UDP Datagrams with Zero
Checksums" [RFC6936] specifies requirements for middleboxes and
tunnels that need to traverse middleboxes.  Tunnel protocols intending
to use a zero UDP checksum need to ensure that they have defined a
method for handling cases when a middlebox prevents the path between
the tunnel ingress and egress from supporting transmission of
datagrams with a zero UDP checksum.  This is especially important as
middleboxes that conform to RFC 2460 are likely to discard datagrams
with a zero UDP checksum."

> Joe