At 07:58 AM 8/7/00, =?iso-2022-jp?B?GyRCOzNLXE9CSScbKEI=?= wrote:
>From: Olafur Gudmundsson <[EMAIL PROTECTED]>
>Subject: Re: ENDS0
>
> > I discussed this with the IPng WG chairs yesterday, and
> > one of them suggested that the message-size draft actually mandate
> > EDNS0 for hosts with IPv6 installed. This is a stronger requirement
> > than I was willing to make, but the other chair suggested to
> > ask the working group if they thing this is a good idea.
>
>Just for clarification. Does this mean dropping my proposal? Or pick
>up both and put them into a draft of IPv6 host requirement?
Do both.
> > Discussions on if EDNS0 should be mandated for IPv6 capable hosts
> > should take place here on ipng mailing list.
>
>OK.
>
>I would like to propose as follows:
>
>(1) DNS resolvers MUST implement EDNS0 if they support IPv6 transport
> or AAAA/A6. Such resolvers SHOULD specify 2048 (*1) bytes as
> buffer size to servers. (This requires larger IPv6 reassemble
> buffer than the minimum, ie 1500.)
>
># (*1) need to discuss an appropriate size
>
>(2) DNS servers MUST implement EDNS if they support IPv6 transport or
> AAAA/A6. They MUST assume client's buffer size is 1024 (*2) if
> clients doesn't specify their buffer size by ENDS0.
>
># (*2) 1024 comes from the IPv6 minimum MTU, 1280 = 256 + 1024.
As I mentioned in the DNSEXT meeting, 1024 is unacceptably low.
1220-1240 is the number I'm thinking about. This is driven by DNSSEC
and the need to have multiple large signatures in certain high level
zones such as ".", "COM" etc.
As for worries about this causing fragmentation I humbly disagree, for the
following reasons:
1. DNS query is unlikely to traverse multiple tunnels to local server.
2. DNS query to a remote server is unlikely to traverse through a
IPSEC tunnel.
Thus we do not need to worry about extension headers at all and
can go to the upper limit of what IPv6 allows.
Olafur
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