More progress. Actually, I am not installing on ubuntu 10.04 (lucid), but rather mythbuntu 10.04, which is a 10.04 derivative that removes all the stuff not necessary for mythtv. Therefore, extra packages need to be added. I started with the debian specific list in MD5.debian.
So far, this is what I did:
1. Install mythbuntu 10.04 from CD. http://www.mythbuntu.org/10.04/release
2. Enable mythbuntu updates, and install them (directions at http://www.mythbuntu.org/auto-builds).
3. Install dbconfig-common and postfix-policyd (sudo apt-get install dbconfig-common postfix-policyd). Create the database for postfix-policyd when asked.
4. Install postix and dovecot. (sudo apt-get install dovecot postfix)
5. Download and untar iRedMail 0.6.0. (wget http://iredmail.googlecode.com/files/iR … 0.tar.bz2; tar -jxvf iRedMail-0.6.0.tar.bz2).
6. Install iRedMail dependencies. install all packages in pkgs/MD5.debian (EXCEPT postfix-policyd) using apt-get, and pkgs/MD5.misc. I copied the latter into pkgs/MD5.ubuntu.lucid, and ran the get_all.sh script to take advantage of it detecting Ubuntu lucid. There is a fix for jaunty to create a missing postfix-policyd table in mysql (blacklist_dnsname), that isn't picked up tor lucid, but the updated postfix-policyd installed in step 3 has fixed that bug).
7. Ran iRedMail.sh but JUST create the config file.
8. Because Mythbuntu installs a LAMP stack, I edited conf/global to set USE_EXIST_AMP to 'YES' instead of 'NO' and conf/mysql to set MYSQL_FRESH_INSTALLATION to 'NO' instead of YES.
9. Then I reran iRedMail.sh and accepted the already-created config file.
Well, after all that restarting things and connecting to the server /mail, /ldap , and mysql gave me what was expected, but I could not log in as the first mail user (www@<domain>). Further, neither dovecot nor postfix were recognizing the first www user. Not sure how to debug their interaction with slapd.
At this point, I am open to suggestions. I suspect that much of what I did would work for stock Ubuntu 10.04 (lucid), perhaps with less of a need to install all the packages that already ship with it. The biggie was getting postfix-policyd to install.
On edit: I also had to install php5-ldap: sudo apt-get install php5-ldap.