mailinabox/conf/fail2ban/jail.local

# Fail2Ban configuration file for Mail-in-a-Box

# JAILS

[ssh-ddos]
enabled  = true

[sasl]
enabled  = true

[dovecot]
enabled = true
filter  = dovecotimap
findtime = 30
maxretry = 20

[recidive]
enabled  = true
maxretry = 10
Cleanup blank lines, comments and whitespace to make it easier to follow 2015-07-02 09:19:37 +00:00			`# Fail2Ban configuration file for Mail-in-a-Box`

Configure fail2ban jails to prevent dumb brute-force attacks against postfix, dovecot and ssh. See #319 2015-03-08 00:13:55 +00:00			`# JAILS`

			`[ssh-ddos]`
			`enabled = true`

			`[sasl]`
			`enabled = true`

			`[dovecot]`
			`enabled = true`
			`filter = dovecotimap`
Ultra safe dovecot findtime and maxretry settings Explicitly set the existing extremely safe timings and counts for the dovecot jail rather than change the global [DEFAULT] and inherit it for this one jail. These settings are far too safe so a future PR will increase security here. 2015-07-06 07:34:26 +00:00			`findtime = 30`
			`maxretry = 20`
Activate FAIL2BAN recidive jail Recidive can be thought of as FAIL2BAN checking itself. This setup will monitor the FAIL2BAN log and if 10 bans are seen within one day activate a week long ban and email the mail in a box admin that it has been applied . These bans survive FAIL2BAN service restarts so are much stronger which obviously means we need to be careful with them. Our current settings are relatively safe and definitely not easy to trigger by mistake e.g to activate a recidive IP jail by failed SSH logins a user would have to fail logging into SSH 6 times in 10 minutes, get banned, wait for the ban to expire and then repeat this process 9 further times within a single day. The default maxretry of 5 is much saner but that can be applied once users are happy with this jail. I have been running a stronger version of this for months and it does a very good job of ejecting persistent abusers. 2015-07-06 07:53:14 +00:00
			`[recidive]`
			`enabled = true`
			`maxretry = 10`