Re: No Place Left to Hide on Tomorrow's Net?

[Nick FitzGerald <nick () virus-l demon co uk>]

der Mouse wrote:

> > IIRC, certain bits of DECnet (or at least, certain bits of DEC
> > hardware we had implementing critical pieces of our DECnet) would
> > only talk to MACs that started with (one of) the DEC manufacturer
> > prefixes,
>
> It's been a while, so I may have this wrong (and it may depend on which
> DECnet Phase we're talking about), but as I recall, it was actually
> that DECnet tried to reach a machine at a MAC address derived directly
> from its DECnet address (the DECnet node number got a fixed set of bits
> prepended to it).  I don't remember exact details, but it was something
> like node 14:711 (binary 001110 1011000111, hex 3ac7 after regrouping)
> being assumed to be at 0a:00:00:01:3a:c7, the 0a:00:00:01 part being
> constant and part of the spec for that phase of DECnet.

That rings way more bells than I thought were still hanging in that 
particular belfry...

Scary!   8-)

> Yes, this put them in a part of the MAC address space assigned to DEC,
> but it didn't depend on having a DEC card, just on having one whose MAC
> address could be set by software (these days that's all of them, but
> back in the earlier days it wasn't).  ...

BUT that "coincidence" wasn't, and was by design -- originally DEC only 
conceived of this working across/between their own equipment, no??

> ...  Of course, it also required
> software that knew how to set the MAC, but that was just part of having
> a DECnet stack that could handle that interface.

Ahh yes -- the dim dark magic of making almost anything talk to almost 
anything else "back then"...

At times I kinda wish things were still like that -- all this 
plug'n'play stuff with "everything enabled by default regardless of the 
security and performance implications" makes every Tom, Dick and Harry 
really dangerous.


Regards,

Nick FitzGerald

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