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Re: About Teredo authentication indication



> In draft-huitema-v6ops-teredo-02.txt it is said in section 5.1.1 that
> "Both ID-len and AU-len can be set to null values if the server does
> not require an explicit authentication of the client.".

FYI, that's what all 3 Teredo implementation I know do (Windows
 Advanced Networking, ng_teredo and miredo).

> When both the
> client identifier and the authentication value are set to null, the
> authentication indication gets a total length of 13 bytes. In such a
> case, the encapsulated IPv6 packet will not start from a memory
> address that is divisible by 4. Doesn't this cause problems on
> platforms that need to worry about memory alignment?

Yes. With the current specification, it's necessary to move the packet
in memory prior to reading/writing the Origin indication and/or the
encapsulated IPv6 packet header.

Unfortunately, mandating properly aligned Authentication header would
break existing implementations. That said, Teredo does not really work
at the moment.

-- 
Rémi Denis-Courmont
http://www.simphalempin.com/home/infos/cv.shtml.en

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