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RE: renumbering and roaming

  • From: Paul Flores
  • Date: Mon May 18 17:22:37 1998

Hash: SHA1

> In message <[email protected]>, Karl Denninger writes:
> >> After several discussions, we came up with this solution
> that we think
> >> works well to support standard services for roaming users:
> >>
> >> Support a .local. root domain in your DNS servers.  Examples of DNS
> >> hostnames would be mail.local., ntp.local., news.local.,
> etc.  When a
> >> roamer dials up he generally uses the DNS servers assigned
> by the NAS;
> >> these addresses would be authoritative on a provider-by-provider
> >> basis.  If all networks supported this schema all users
> could simply
> >> have these addresses coded into their client software and would
> >> connect to the proper machines as they differ on various networks.
> >>
> >> iPass is currently building an Internet-Draft specifying
> the details
> >> of this approach.  What do you think?
> >That doesn't work; too many of those things must be
> hard-coded numbers
> >(specifically, the DNS servers).
> What has to be hard-coded besides the DNS servers?  Once you have a
> DNS server assigned (which is typically done by the NAS anyway) the
> rest is simple.

Ass-umeing (never ass-ume, right) that the NAS supports the LCP extensions.

> In our experience, well over 90% of roaming users (which
> excludes UNIX
> and Mac users) use dynamically-assigned DNS servers.  Clearly this
> approach won't work for those clients that don't support the LCP
> extensions, but we consider this "Best Current Practice."

Okay, that is reasonable. Why not take the extra step of reserving some
'internal' IP space, and make it work with 100% of the clients?

>  Those
> clients that can't use dynamic DNS server assignment will have to use
> the home ISP's services.

Combine a non-advertised, reserved subnet with the .local TLD. (I might
point out, that clients not using the the local .local assignments, will get
the 'home ISPs' services addresses. I am not quite sure if you meant all
their services or just DNS, but that is an important distinction to make

I would also point out that ANY failure of the local DNS would render
everything useless to the roamer. If you had a combination of both, you
could actually put the hardwired IPs/ .local domains in a host file on the
roamer's machine. You would sacrifice some flexibility, but would probably
solve a few nagging details this way. (on second thought, this is probably
not such a good idea... :> )

> We consider it important to make sure as many NASes and PPP clients as
> possible support dynamic DNS.  About the only major obstacle to that
> is OT/PPP (MacOS) and, to a lesser degree, UNIX.
> >.LOCAL along with defined addresses, declared as
> "non-routable" (ie: local
> >only) *DOES* do the trick.
> Routability and IP address definitions are secondary to the problem
> we're discussing here--the ability for roamers to use local services
> provided by the POP provider.

Exactly. Why does it matter if you use DNS, private IP space, or a
combination of both. IMHO, both provides the most flexibility.

>  Let DNS do the work for you.  I don't
> see the need to force IP assignments on the Internet community.

Force? I don't think force is the word. No one forces people to use reserved
IP space for their private networks. To me, this is simply an extension to
1918, with the addition of some very sensible service layer options for
Service Providers.

Paul Flores
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