Odd problem in 7.4.2?

I have an odd problem where PostgreSQL 7.4.2 will fail to run if the
machine it's installed on is moved to another network. The configuration
is stock (i.e. no modifications to the configuration) running on Linux
(Red Hat ????, it's a 2.4 kernel). I set up the machine with PostgreSQL
and create the database on one network, and connections made to it are
fine. If I move the machine to another network and bring it up,
PostgreSQL fails to run.

Since PostgreSQL is configured by default to run only on Unix sockets,
moving the machine shouldn't cause the server to fail to run, right?
What am I missing?

Sorry for the lack of specific info. I'm getting most of my information
second hand and after the fact. Any help you can give would be
appreciated. Thanks!

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