[ih] Memories of Flag Day?

[Andrew G. Malis]

Miles,

I wrote the IMP code to enforce the flag day and ran the transition from
the NOC.

To prepare for the flag day, we added a new bit to each port's
configuration in the IMPs. The bit said whether or not a port was allowed
to use the NCP host-host protocol (port 0). If the bit was off, then NCP
host-host packets were discarded by the IMPs.

There was a defined procedure in place well prior to the cutover for
approving exceptions to the no-NCP policy.

On January 1, I pulled the switch to flip the bits from "on" to "off"
except for the pre-approved list of exceptions.

A good number of hosts made the deadline, but additional exceptions were
approved as the phone calls started coming in. The exception list continued
to grow in the first few days of 1983, but as hosts gradually got their
TCP/IP stacks working, their NCP permission was turned off.

As I recall, the exception list quickly shrank, and by the end of the year
there were very few NCP-only hosts left. There was certainly some amount
of pain involved, but NCP would have hung around for much longer if the
switchover hadn't been enforced.

Cheers,
Andy


On Sun, Aug 6, 2023 at 7:35 AM Miles Fidelman via Internet-history <
internet-history at elists.isoc.org> wrote:

> Hi Folks,
>
> Does anybody have some memories of the TCP/IP Flag Day they can share?
>
> I'm doing some writing about "how network ecosystems develop" looking at
> how the Internet evolved from the days the net was a gleam in a few
> people's eyes, Licklider distributed his famous memo, the NWG & IETF
> evolved, Flag Day, etc.  Also looking at the Environmental Movement
> (Earth Day, Whole Earth Catalog, ...), FOSS, Crisis Mapping,
> Entrepreneurship Support, Makers - all of which I've been up close and
> personal with, and now trying to document some common threads & techniques.
>
> A particular focus is on organizing for significant
> changes/transformations - like the transition to IP that pretty much
> marks the birth of the Internet as we know it.  Hence a particular
> interest in what led up to the Flag Day, and how folks responded.
>
> In particular, I'm wondering how folks organized at various network
> sites (universities, military bases, etc.) to respond to the mandate.
> Working groups, plans & programs, that sort of thing. How did folks get
> their act together?
>
> Anybody have any stories they can share?
>
> Thanks Very Much,
>
> Miles Fidelman
>
> --
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> In practice, there is.  .... Yogi Berra
>
> Theory is when you know everything but nothing works.
> Practice is when everything works but no one knows why.
> In our lab, theory and practice are combined:
> nothing works and no one knows why.  ... unknown
>
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