Hi Marc,
If you read the link keenly -
Debugging/Rawlog - Dovecot Wiki - you will realize that you need to do some stuff.
I have done them and they produced the results.
Edit /path/to/dovecot/conf.d/10-master.conf and add the following:
Under this block:
add executable = imap postlogin to the block that has
service imap {
....
...
}
Then create another block in the same file as follows:
service postlogin {
executable = script-login -d rawlog
unix_listener postlogin {
}
}
Identify the user for whom you want the rawlogs:
Now do the following:
mkdir dovecot.rawlog
chown -R 26:26 dovecot.rawlog
systemctl restart dovecot (or however you do it in CentOS)
Now login to imap as the user .. perform some operations.
PS: Adapt as necessary. I tested this on FreeBSD with dovecot- 2.3.11.3
Ignore the /tmp/rawlog/%u portion of the HOWTO. I did it too, but there was nothing in /tmp/rawlog/ even though I created the directory and did chmod 1777 /tmp/rawlog.
Adios.