Subject: IPv6MIBs IPv4-mapped address questions

From: "Kristine Adamson" <[email-masked]>
Date: Mon, 23 Jul 2001 14:43:09 -0400

I posted the following questions to this mailing list on 6/22 but I have
not received any response yet.  Now that the proposed MIBs are IETF
internet drafts should I still expect an answer to my questions on this
mailing list or should I repost my questions somewhere else?

> I am an SNMP developer and have just subscribed to this mailing list, so
I
> apologize if there has already been a discussion on this subject.  I
> noticed that the IPv6 MIB Design Team internet drafts for the revised TCP
> and UDP MIBs, define version neutral MIB tables.  For a server
application
> that opens an AF_INET6 socket and binds to the unspecified address
(without
> setting the IPv6_V6ONLY socket option), should there be two entries in
> these MIB tables, one with the local address as IPv4/INADDR_ANY  and one
> with the local address as IPv6/unspecified?  Or should there be one entry
> with the local address as IPv6/unspecified?  What if the server
application
> opened an AF_INET6 socket and bound to an IPv4-mapped address?  Would
there
> be one entry in the tables with the local address as IPv4/address or as
> IPv6/IPv4-mapped address?  I think my real question is, are the table
> entries supposed to reflect the IP address type from the view of the flow
> of the packets on the network, or from the viewpoint of the address
family
> of the socket with which the connection/listener is associated?

Thanks!

Kristine Adamson
IBM Communications Server for MVS: TCP/IP Development
Internet e-mail:[email-masked]

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From: Bill Fenner <[email-masked]>
Date: Tue, 24 Jul 2001 00:48:29 -0700

Kristine,

  I'm sorry I missed your email the first time you sent it.

> For a server application
> that opens an AF_INET6 socket and binds to the unspecified address (without
> with the local address as IPv6/unspecified?

This is one of the open issues.  I think we've been leaning towards
InetAddressType == Unknown, and a zero-length InetAddress.

> What if the server application
> opened an AF_INET6 socket and bound to an IPv4-mapped address?  Would there
> IPv6/IPv4-mapped address?

This is a good question, and one which I hadn't thought of.

There should be a canonical answer, since otherwise managers will have
to check both IPv4 and IPv6-mapped addresses if they're looking for a
specific row.  That implies that the answer should represent the AF
on the wire, not necessarily the socket, and perhaps the MIBs should
prohibit using InetAddressType=ipv6 and IN6_IS_ADDR_V4MAPPED(InetAddress).

  Bill

---

From: "Kristine Adamson" <[email-masked]>
Date: Tue, 24 Jul 2001 08:07:19 -0400

Bill,
   Thanks for your responses.  Do you think some of these open issues will
be discussed during the upcoming IETF meeting in London?  I see you are on
the agenda to present the MIBs.

Thanks!

Kristine Adamson