Currently the Directional host address type is pretty useless,
since it's only useful in application protocols that a) use
KRB-PRIV/KRB-SAFE messages (so: not GSS-API applications), and b)
state in their specs to use Directional, or otherwise provide for
negotiation of host address types. There are no such protocols
that we care about except -since we control it- iprop. But even
for iprop it'd be better to switch to GSS-API.
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