Am 19.04.2020 um 14:58 schrieb Jeffrey Walton: > The offending host is 59.64.129.175. To err on the side of caution we > attempted to block the entire netblock. According to whois data, > that's 59.64.128.0-59.64.159.255. > > iptables -A INPUT -s 59.64.128.0/19 -p TCP -j DROP There was no comment so far that the order of the iptables rules matters. With your command you append to the existing rules. If would be without effect in case there is a rule in order before which permits the traffic you try to block. > After reboot cpu usage is still high and access_log still shows > useless requests from the host: > > 59.64.129.175 - - [19/Apr/2020:08:53:53 -0400] "GET > /w/index.php?title=Special:WhatLinksHere&limit=50& > printable=yes HTTP/1.1" 301 311 > > I seem to be missing something. That's not surprising since I am not a > server administrator. > > How do I filter the unwanted traffic from the netblock? The iptables rules should be saved in /etc/sysconfig/iptables to be read in at boot time (or when the iptables services gets restarted). Alexander