следното проблемче с IMAP 
tar jxvf courier-imap-3.0.8.tar.bz2

cd courier-imap-3.0.8

 ./configure --prefix=/usr/local --exec-prefix=/usr/local
 --with-authvchkpw --without-authdaemon --without-authldap
 --disable-root-check --with-ssl
--with-authchangepwdir=/usr/local/libexec/authlib

make && make install-strip && make install-configure
cd /usr/local/etc

cp imapd.dist imapd

cp imapd-ssl.dist imapd-ssl

/usr/local/sbin/mkimapdcert
cp /usr/local/libexec/imapd.rc /etc/rc.d/rc.imap
cp /usr/local/libexec/imapd-ssl.rc /etc/rc.d/rc.imaps
/etc/rc.d/rc.imap start
/etc/rc.d/rc.imaps start
telnet localhost 143

трябва да се получи ...
Trying 192.168.1.10...
Connected to 192.168.1.10.
Escape character is '^]'.
 * OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE
 THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE
 STARTTLS] Courier-IMAP ready. Copyright 1998-2003 Double
Precision, Inc. See COPYING for distribution information.
a login postmaster@mydomain.com my_password
a OK LOGIN Ok. (successful login!)
a logout (logs you out)
* BYE Courier-IMAP server shutting down
a OK LOGOUT completed
Connection closed by foreign host.

 Hint: The "a" that you see before my login commands is
required. 
но се получава това 
telnet localhost 143
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
 * OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE
 THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL
 ACL2=UNION STARTTLS] Courier-IMAP ready. Copyright 1998-2005
 Double Precision, Inc.  See COPYING for distribution
information.
login postmaster@blabla.org pass_nqkaf
login NO Error in IMAP command received by server.
защо се получава така ?

 Трябва да е "a login postmaster@blabla.org pass_nqkaf" , а
не "login postmaster@blabla.org pass_nqkaf"