Linux系統中Fail2ban是一款保護服務器免受網絡攻擊的工具，Fail2ban可以通過黑名單來禁止IP訪問。既然有被禁止的IP，那麼問題來了，CentOS系統如何把IP從Fail2ban黑名單中移除。
如何列出被禁止的 IP要查看所有被禁止的 ip 地址，運行下面的命令：
# iptables -L
Chain INPUT （policy ACCEPT）
target prot opt source destination
f2b-AccessForbidden tcp -- anywhere anywhere tcp dpt:http
f2b-WPLogin tcp -- anywhere anywhere tcp dpt:http
f2b-ConnLimit tcp -- anywhere anywhere tcp dpt:http
f2b-ReqLimit tcp -- anywhere anywhere tcp dpt:http
f2b-NoAuthFailures tcp -- anywhere anywhere tcp dpt:http
f2b-SSH tcp -- anywhere anywhere tcp dpt:ssh
f2b-php-url-open tcp -- anywhere anywhere tcp dpt:http
f2b-nginx-http-auth tcp -- anywhere anywhere multiport dports http，https
ACCEPT all -- anywhere anywhere state RELATED，ESTABLISHED
ACCEPT icmp -- anywhere anywhere
ACCEPT all -- anywhere anywhere
ACCEPT tcp -- anywhere anywhere tcp dpt:EtherNet/IP-1
ACCEPT tcp -- anywhere anywhere tcp dpt:http
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited
Chain FORWARD （policy ACCEPT）
target prot opt source destination
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited
Chain OUTPUT （policy ACCEPT）
target prot opt source destination
Chain f2b-NoAuthFailures （1 references）
target prot opt source destination
REJECT all -- 64.68.50.128 anywhere reject-with icmp-port-unreachable
REJECT all -- 104.194.26.205 anywhere reject-with icmp-port-unreachable
RETURN all -- anywhere anywhere
如何從 Fail2ban 中移除 IP
# iptables -D f2b-NoAuthFailures -s banned_ip -j REJECT
以上就是CentOS系統把IP從Fail2ban黑名單中移除的方法了，把IP地址從Fail2ban黑名單中移除了以後，也就解除了該IP對服務器訪問的限制。