Usually I use pfsense as main firewall with snort blocking all kind of scans and others.
Fail2ban triggering after 3 unsuccessful tries and for last iptables if Linux or ipfw If Freebsd
Keep pfsense synced with intrusion lists is an must have.
And for last, bans are not temporary on my setup, are forever, except if an real user after validate his info / data calls to unblock him.
There's some guides around about deal with post screen, but never get that working... RBL and spamhaus lists on mail server and on DNS are another must have.
Good luck
Atenciosamente,
Alexandre Fernandes Pedrosa
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