I'm studying courier imap 1.2 at the moment, and have some questions:

1) (BUG): When configuring in authlib, configure stops with the following error message:

./configure: test: argument expected configure: error: ./configure failed for authlib

The reason for this seems to be missing quotes around a variable in authlib/configure, line 2678, which presumably happened to have a null value:

if test -x $MYSQL_CONFIG

2) What, exactly, is gdbm/db used for? The INSTALL document says "for certain functions". I can tell that they are used by the userdb auth module and couriertcpd. Anything else?

I prefer Berkeley DB (db). Can I use use version 2.x, or does courier imap require Berkeley DB version 3.x?

3) What (and when) is the file etc/imapd.cnf for? I can't find any references to it in the docs.

4) Are there any issues regarding the use of tcpserver instead of couriertcpd? As far as I can tell, they are very similar except that couriertcpd can also limit the number of connections from the same networks. Can I use tcpserver if I wish, with no problems?