[Exim] Delivery to user@localhostname - best practice?

Hi

I have an exim4 server running on Debian, whose local host name is ganymede,
that handles internet mail for somedomain.dyndns.org; this part of things is
working fine.

However, if I (peter) mail someone else on the local box like so:

$ mail karsten
Subject: Test
Wibbly fish
.
$

I'll get a frozen message in the queue and a message to postmaster with
"karsten@ganymede: Unroutable address" in it.

To fix this, I edited /etc/exim4/conf.d/main/02_exim4-config_options to set
the following:

sender_unqualified_hosts = ganymede
recipient_unqualified_hosts = ganymede

Now, this seems to have brought things round; however, what I'm not sure of
is if this is The Right Way of doing this.

Am I doing The Right Thing?

Regards

Peter.
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