[imp] login logging

[e t]

Hello,

i'm using

imp-4.1.4_1 which seems to be the latest/stable on FreeBSD 6.2

I would like to know if there is any sort of way for me to logg any
successful logins.

Upon a failed login I see this into the log files, yet there is nothing upon
a successful login.

"/var/log/httpd/access_log.0.bz2:81.199.179.19
webmail.blah.com/webmail.blah/php.fcgi - [23/Jul/2007:19:56:42 -0400]
"GET
/horde/imp/login.php?imapuser=demo%40bogusdomain.com&logout_reason=failed
HTTP/1.0" 200 2765 "http://webmail.blah.com/horde/imp/login.php"
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)"



We use IMP as a frontend to a few of real IMAP servers and we have been
getting spammed from people loggin in
with real accounts whose passwords are weak.  We have almost 16.000+ virtual
accounts and having them rotate the password
is not a solution, thus we would like to match

1)the IP which is given on field 1 of the above posting
2)to any possible information we may logg from Horde


Thanks.