Some examples use non-2606 domains.
I suggest the following general replacements, which seem to make all the
examples and text conflict-free:
foo.org -> foo.example.org
bar.org -> bar.example.org
d.bar.org -> d.example.org
xyz.com -> v.example.org
ijk.org -> example.com
foo.com -> example.com
physics.foo-u.edut -> physics.example.edu
specific.generic.com -> example.com
ISIF.USC.EDU -> ISIF.EXAMPLE.EDU
bar.com -> example.net
There's also an occurence of isi.edu, but I cannot bring myself to
suggest removing Jon Postel's email address from 821ter ;)
Arnt