Install and configure container fail2ban ( acces to SSH )

Hello.

I have UnRAID version 7.3.1 and I've installed the fail2ban container (linuxserver) for a little extra protection.

In the template, I have the following information:

Path /var/log -> /var/log

Appdata -> /mnt/user/appdata/fail2ban

Then, inside the fail2ban directory, I created a jail.local file with the following configuration:

[sshd]

#mode = normal

enabled = true

port = ssh,9876

bantime = 24h

findtime = 1h

maxretry = 2

logpath = %(sshd_log)s

backend = %(sshd_backend)s

But I keep getting the following error:

2026-06-01 23:57:31,631 151F11834B28 INFO Loading files: ['/etc/fail2ban/filter.d/common.local']

2026-06-01 23:57:31,631 151F11834B28 INFO Loading files: ['/etc/fail2ban/filter.d/common.conf', '/etc/fail2ban/filter.d/sshd.conf']

2026-06-01 23:57:31,634 151F11834B28 ERROR Failed during configuration: Bad value substitution: option 'action' in section 'sshd' contains an interpolation key 'banaction' which is not a valid option name. Raw value: '%(action_)s'

2026-06-01 23:57:31,634 151F11834B28 DEBUG Exit with code 255

I have also tried creating a /fail2ban/jail.d/sshd.local with the same configuration and I got the same error.

I know I have to access the RAID array from outside via VPN (that's how I have it set up), but I also want to protect access via SSH, just in case.

What am I doing wrong that I'm missing? Can anyone help me out?

Thanks