how does psql know where to go?

I have two machines bonny and clide which share a NFS disk
(which contains the postgres binarys)

bonny is running a postgres database 'testdb' on a local disk
using the binarys on the NFS disk (/nfs/postgres/).

If I log into clide and run '/nfs/postgres/bin/psql testdb'

It connects to postgres on bonny and creates a terminal session.

How does it know where to connect and how do I stop it?

I want to run a backup database on clide and don't want any
confusion as to which database I'm working on!.

I've stripped out all references to postgres in the enviroment
and I set listen_addresses = 'localhost' on the database on bonny
which I would assume would prevent external connections.

--
Michael
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Michael John Lush PhD            Tel:44-1223 492626
Bioinformatician
HUGO Gene Nomenclature Committee    Email: hgnc@genenames.org
European Bioinformatics Institute
Hinxton, Cambridge
URL: http://www.genenames.org
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