[horde] Logfile - disable hostname lookups

[Markus Winkler]

Hi,

my Horde setup has:
$conf['log']['enabled'] = true;
$conf['log']['name'] = '/var/log/horde.log';

I would like to check /var/log/horde.log with fail2ban for entries like this:

2022-03-19T08:52:50+01:00 NOTICE: HORDE Guest user is not authorized for 
Horde (Host: hostglobal50env1.com). ...

This works fine so far, fail2ban detects these entries. But: as you can see 
for 'Host' it resolves the corresponding IP address (as seen by the web 
server, I assume; and btw: in the Apache config I have 'HostnameLookups Off'):

$ host 109.237.103.9
9.103.237.109.in-addr.arpa domain name pointer hostglobal50env1.com.

and writes this hostname to the log file. But in most cases there's no 
forward resolution for these hostnames, like in this example:

$ host hostglobal50env1.com
Host hostglobal50env1.com not found: 3(NXDOMAIN)

And so fail2ban cannot create an entry for the iptables chain.

Long story short: is it possible to disable hostname lookups so Horde only 
logs the ip address?

Thanks and best regards,
Markus