On 1 Dec 2008, at 09:00, Hesham Soliman wrote:
=> Well, I'm not sure how a NAT can do that. You mean the NAT will
parse the binding update message deep inside the IPv6 extension
header in the inner IP packet? This is where the original address
is preserved. To do that, a NAT would have to understand the
various MIPv6 options, and if it did, it would know not to do
that :) The inner header is IPv6, so a NAT should not touch that.
My understanding from the STUN work is that NATs have been observed
which rewrite any sequence of four aligned bytes matching the source
IP address, irrespective of its location within the packet (section
15.2 of RFC 5389).
=> Sounds freightning! May be we need to mandate encryption and
hope that no 4-byte sequence matched the IP address? What do they
do with encrypted packets? How do they know they're encrypted?
One would assume these broken devices will potentially corrupt
encrypted packets, the same as they will potentially corrupt any
other packet. Hiding the source address when it appears in the
payload (either by encryption, or using some trivial obfuscation as
does STUN) simply reduces the probability of such corruption so it's
no longer 100% guaranteed that the payload will be mangled.
--
Colin Perkins
http://csperkins.org/
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