pg_hba.conf is inscrutable to me

Hello all. I hope this is the right place for this question. On a
machine called falstaff.trgrdc.mc.xerox.com, IP address 13.137.84.27,
I've got the following pg_hba.conf:

local all trust
host all 13.137.84.27 255.255.255.255 trust
host all 127.0.0.1 255.255.255.255 trust
host all 0.0.0.0 0.0.0.0 trust

While logged on to this machine as UID postgres, I do the following:

psql -h falstaff.trgrdc.mc.xerox.com

... and get the following message:

Connection to database 'postgres' failed.
No pg_hba.conf entry for host 13.137.84.27, user postgres, database
postgres

... tried lots of variations on the pg_hba.conf, none of which worked.
I can't see what's wrong with this one. Any
suggestions?

--
Robert Miller
The Rochester Group
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Rochester, NY 14607

I will say one thing. It is amazing how many drivers, even at the
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