[Courier-imap] authdaemond log no rhost

[Gregor H. <cou...@gr...>]

Hello,

I would like to configure a fail2ban rule for authdaemond authentication failures.
Unfortunately the rhost field in the auth.log is empty:

Feb 21 08:35:29 host1 authdaemond: pam_unix(imap:auth): authentication failure; logname= uid=0 euid=0 tty= ruser= rhost= user=user1

How can I get the remote IP Address?
I am using Debian stable stretch.

Thank you.
--
Greg