To find out whether any particular IP is blocked or not on the server =>
# route -n |grep <IP Address> ::
for example: #route -n |grep 58.8.66.156
To unblock an IP =>
# route del <IP Address> reject
::for example: #route del 58.8.66.156 reject
To block an IP =>
# route add <IP Address> reject
:: for example: #route add 58.8.66.156 reject
Or
How to check that ip is blocked or not:
#cat /etc/csf/csf.deny
check whether that the ip which you searching is present in the file and if you want that insert a ip in file to deny then after inserting a ip give the command:
#csf -r
Add ip in allow file by giving command
# cat /etc/csf/csf.allow // Then give following command
# csf -a ipadress