[CentOS] Netfilter fails to filter traffic from a netblock?

Sun Apr 19 13:26:55 UTC 2020
Anand Buddhdev <anandb at ripe.net>

On 19/04/2020 14:58, Jeffrey Walton wrote:

Hi Jeffrey,

> The offending host is To err on the side of caution we
> attempted to block the entire netblock. According to whois data,
> that's
>     iptables -A INPUT -s -p TCP -j DROP
> After reboot cpu usage is still high and access_log still shows
> useless requests from the host:

Did you actually arrange for your iptables rule to be reinstated at boot?

If you just configure a rule as above, but don't save it, it will
disappear ar reboot.