On Aug 13, 2008, at 4:42 AM, Heiko Schlichting wrote:

All parts of dovecot except deliver uses the result of
hostpid_init() in src/lib/hostpid.c as a hostname which only asks gethostname().

deliver honours environment variable HOSTNAME in src/deliver/ deliver.c:

getenv("HOSTNAME");

and uses the hostname of hostpid_init() as a fallback.

Well, this is actually trying to use the hostname setting from
dovecot.conf. The settings just happen to get passed in environment.

Wouldn't it be consequent to evaluate the environment variable
HOSTNAME in hostpid_init() with fallback to gethostname() and remove the special behavior from deliver? The dovecot master process should export
$HOSTNAME to all childs in this case.

Another alternative would be to make the hostname setting global in
dovecot.conf and have imap processes use that.

Dovecot uses the hostname as part of Maildir file names and
gethostname() is not fully qualified on all operating systems (it is on IRIX but
not on Linux). But unqualified hostnames are not unique and it is frequent
that dovecot hosts are named "mail" oder "imap" as hostname. To distinguish between mail.domain1.com and mail.domain2.net would be easier if
dovecot evaluate $HOSTNAME in all case not just deliver as program imap can
create Maildir files as well.

I always thought that hostnames were unique within the installation
everywhere even without the domain part, and the domain would just
waste disk space in the filenames (and dovecot-uidlist)..