[discuss] Real world Impact of multiple roots

Barry Shein bzs at world.std.com
Wed Jan 29 19:14:49 UTC 2014

Point of Information.

The usual idea for running multiple DNS roots is to use the resource
record class which is 2 bytes (so could support ~2^16 values, ~65,535
co-existing roots!) and is currently always IN though Chaos and Hesiod
are defined in the standards (old MIT experiments.)

I assume this is what Avri is referring to as "schema" though perhaps
not, she might be referring to something more general, but it's in the
same spirit.

THE TECHNICAL PROBLEM is that CNAMES don't have these classes.

CNAMES define aliases so if you want example.com and www.example.com
to point at the same address the typical way to do that is to make one
the Address record and the other a CNAME, an alias to it.

This may sound minor but operationally it would be a huge problem
unless fixed. All sorts of things rely on CNAMEs.

Of course that could be fixed -- add a class field to CNAME RRs, for
example, encourage everyone to rework their zone files and software.

SMOP (Simple Matter Of Programming.)

Also, did anyone mention split-horizons? Ok then, split-horizons (it
probably isn't wortwhile discussing.)

        -Barry Shein

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