Subject: Re: [lisp] [tsvwg] Milestones changed for tsvwg WG

From: [email-masked] (Noel Chiappa)
Date: Thu, 9 Jan 2014 11:16:01 -0500 (EST)

> From: <[email-masked]>

    > any IP/UDP header corruption goes undetected at the endhost because the
    > pseudoheader checksum has been disabled. .. the header corruption takes
    > the packet to some other destination/port, so you don't see it; it's
    > just a drop as far as you are concerned. But it matters for whatever
    > actually receives that corrupted packet on e.g. an altered port value.
    > ...
    > odd behaviour on other applications at the same endpoints (or, with
    > IPv6, in the same network) caused by missent packets with corrupt ed
    > UDP packets? Hey, not your problem. Hey, you're working just fine.
    > It's pollution and tragedy of the commons, basically.
    > When you send with a zero UDP checksum, it's possible for the packet to
    > be received and processed anywhere.

Outlawing use of non-checksummed UDP for tunnels isn't going to _guarantee_
that such packets never show up at a host: malicious or buggy software could
also generate them - as could whatever is hypothetically damaging
non-checksummed UDP tunnel packets.

So hosts have to be able to deal with such packets anyway.

The only question left, then, is 'is this happening often enough to present a
significant processing load to the innocent bystanders' (which I agree would
be problematic). But here I echo Stewart Bryant: what data is there that this
is actually happening often enough to be a problem?

And along those lines, I'm looking at the 'incoming traffic' light on my cable
modem, and it's blinking constantly - port scanners and such, I assume. A few
stray tunnel packets would be lost in that flood.

	Noel