On 11/4/11 5:46 AM, Hector Santos wrote:
Douglas Otis wrote:
>> The way I see it, practically speaking, Ipv6 will bring back the
>> old simple solution of using "Allow IP Relay Tables" and the
>> "Roaming user" issue would be a thing of the past.
> Please notice currently there are 228,848 billion announced IPv6
> /64 equivalent prefixes. A size 65k larger than the entire IPv4
> unicast space. Also note this space is growing exponentially,
> where the chart has become vertical. Have fun keeping up with
I seriously doubt any one system is going to need to record all that,
after all, a site is are only going to record their "protected realm"
A.K.A network of users, partners or known senders just like its
currently done without sweating it. To assume a single system is
going to need to record 228,848 billion of anything, well, is very
ambitious for any single organization.
Doubts about managing each source within this space using CIDR lists is
The term "protected realm" describes inbound MTAs associated with
designated Kerberos services. Kerberos is likely to be an attacked
service. As such it should be offered from distributed and robust
networks, perhaps by third-parties. This service should include
intra-realm communications to indicate which domains were offered
tickets. This information could selectively open firewalls protecting
services within the vast IPv6 environment.
> At the smaller /48 prefixes, 538, 474, 403, 271, and 270 million
> announcements are in Germany, Japan, rest of EU, Australia, and
> Korea respectively. Even so, all /48s represent just .000067% of
> the entire announced space.
The large spectrum of IPv6 is well understood, but IMV, no single
system is going to need to record anything close to these sizes,
unless of course, your company is planning to take over the world.
Hardly. Just guessing, it seems growth will top out at 1.4 trillion (a
million million) /64 equivalent prefixes. This represents a dramatic
increase from 3.8 billion, especially since practices used to dismiss a
sizable portion of IPv4 can not apply. Ignoring an inability to reduce
the monitored space, 370,000 to 1 compression would be required to
utilize resources currently available.
> Placing your inbound servers into a "protected realm" says you wish
> to establish a robust method for accepting messages from legitimate
> domains that you'll take steps to protect.
Lets assume your I-D proposes something really fantastic - that it
can have a high payoff and impact to lower spam.
The goal is to permit a method for defending services to ensure desired
exchanges. You seem to suggest this would be your approach, but
permissions would be referenced by domain rather than by IP address.
Domain names should be easier to manage and can apply even when
What happens to the other AUTH methods? Do we enforce KERBEROS only
The use of Kerberos based upon domain certificates is envisioned to
represent a robust lightweight method to supplant reliance upon source
IP addresses. This might be used only where needed, and might
eventually become the norm. Either way, acceptance is still determined
by inbound MTAs: either based upon source IP address or verified domain
name. Kerberos simply affords an efficient method for the added
validation that perhaps happens every N hours per source.
My concern is the idea that SMTP systems will no longer need to
accept mail from non-authenticated senders for local users and to
move into a mode where all senders are (Kerberos) authenticated. In
other words, the Public Port SMTP network will no longer be public.
That is not the change envisioned. This is to ensure desired exchanges
are able to occur using manageable data-sets.
If enforcement is not mandated, then why would a sender use it? What
benefits do they get over others that using something else? That is
something I would like to know in your I-D.
Again, the protections offered directly benefit senders. It affords a
robust and lightweight basis in which exchanges can be accepted. The
enhanced name based source information directly benefits senders that
might otherwise contend with recipients suffering from resource constraints.