Block Lists
Snort's list of suspicious/malicious IPs to block
Spamhaus's various block lists
Firewall and NSM Rules
Snort Talos, aka Snort VRT Rules
Various Snort Rules; free, registered, and paid
Snort's list of suspicious/malicious IPs to block
Spamhaus's various block lists
Snort Talos, aka Snort VRT Rules
Various Snort Rules; free, registered, and paid