This would inidicate a PHP and/or system issue, not an issue with 
Horde/IMP code (since we are reliant on PHP/system calls to do the 
name resolution for us).

i'm migrating from one server to another ... horde works flawlessly on 
old_box, but i've run into a strange situation on new_box and wondered 
if anyone else had experienced a problem with hostname resolution.

summary: the only valid config in horde :: options :: global options 
:: authentication credentials is server=127.0.0.1 ... similarly the 
only server= value that works for all fetchmail configuration is also 
127.0.0.1 ... localhost does not work at all.

i'm running dovecot and postfix on ubuntu 9-10 and best i can tell, 
everything is working just fine ... i am able to telnet to localhost 
and establish an imap connection:
# telnet localhost 143
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
* OK Dovecot ready.
a login myemail@mydomain.com mypassword
a OK Logged in.

i have dovecot configured to listen only on localhost:143, but i 
changed that to *:143 and restarted dovecot just to make sure that 
wasn't the issue. the test.php returns no critical errors, and 
everything related to imap is installed and working properly. the 
phpinfo() also shows imap as installed/configured.

here's my servers.php settings:
$servers['imap'] = array(
     'name' => 'IMAP Server',
     'server' => 'localhost',
//    'server' => 'fqdn.myhost.net',
//    'server' => '127.0.0.1',
     'hordeauth' => false,
     'protocol' => 'imap/notls',
     'port' => 143,
);

note: i have tried to get this to work by changed out servers.php and 
using the loopback and/or the fqdn, but it doesn't really seem to make 
a difference.

unless i specify 127.0.0.1 under authentication credentials screen, i 
cannot get into imp

once i am inside imp, the only way i can get fetchmail to work is to 
specify 127.0.0.1 under server. if i put in localhost, i get the 
following message when i try to fetch mail:
let me know what additional info i can provide and/or what 
tests/config changes you would like me to make to assist in getting 
this working.

thanks,
-e