Quote:
dup loop

/d[y]oop loop/ (also "dupe loop") [FidoNet] An infinite stream
of duplicated, near-identical messages on a FidoNet echo,
the only difference being unique or mangled identification
information applied by a faulty or incorrectly configured
system or network gateway, thus rendering dup killers
ineffective. If such a duplicate message eventually reaches a
system through which it has already passed (with the original
identification information), all systems passed on the way
back to that system are said to be involved in a dup loop.

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