dovecot --hostdomain

[dovecot at nspace.de]

Hi,

I'm currently debugging replication issues and I found that both servers 
answer to a "dovecot --hostdomain" simply with

localhost

 From what I've read, this can lead to problems.
Where do I configure the dovecot hostdomain name? The machine itself has 
a valid name in /etc/hostname

Thanks,
Thomas