Issues with draft-huitema-v6ops-teredo-02.txt

[Rémi Denis-Courmont <rdenis@simphalempin.com>]

	Hello,

I've got a few questions regarding draft-huitema-v6ops-teredo-02.txt

> 5.1.2 Maximum Transmission Unit
> 
> The default link MTU assumed by a host, and the link MTU supplied by
> a Teredo server during router advertisement SHOULD normally be set
> to the minimum IPv6 MTU size of 1280 bytes [RFC2460].

Should the server embed a MTU in its RA?

> 5.2.1 Qualification procedure
(...)
> The client selects a secondary IPv4 server address, and
> repeats the procedure, the cone bit remaining to the value zero.

How is the secondary IPv4 server address determined?
The implementation currently shipped with Windows XP seems to increment 
the primary server address by one, but that behavior is not documented 
in the spec.

> 5.3 Teredo Server specification
(...)
> The Teredo server
> waits for incoming UDP packets at the Teredo Port, using the IPv4 
> address that has been selected for the service. In addition, the
> server is able to receive and transmit some packets using a
> different IPv4 address and a different port number.

I thought the port number was 3544 in both cases. Is that not the case, 
and, if so, how is the port determined by the client?

> 5.4.1 Transmission by relays to Teredo clients
(...)
> Before processing these packets, the Teredo Server MUST check that
> the IPv4 destination address embedded in the Teredo IPv6 address is
> in the format of a global unicast address; if this is not the case,
> the packet MUST be silently discarded.

I'm fairly confused there: Is it the server's or the relay's job to 
check the "IPv4 destination address embedded in the Teredo IPv6 
address" ?

I admit servers should do the check, as they should not blindly trust 
packets from relays. But as I read the following sentence:

> The relay then checks if there is an entry for this IPv6 address in
> the list of recent Teredo peers, and if the entry is still valid.

I assume it is the relay's job. Doesn't that need a bit of 
clarification?

Sincerely,

-- 
Rémi Denis-Courmont