You'll need to increase it if you want to use a large block list. Notice the maxelem property which sets the maximum number of elements in the set. The identifier LEVEL1 is the name of the set, which will be used later in the firewall rule. For modern kernels, the hash:net type works the best: ipset create LEVEL1 hash:net maxelem 262144 Next, you'll need to create an IP set to hold the data from a blocklist. You will also need the iptables and ipset utilities, as well as several standard command line tools like curl, cut, gawk, grep, and gunzip. You could also compile these features as modules and insert them at runtime: for mod in ip_tables ip_set xt_set ip_set_hash do modprobe $mod done

We'll use the kernel packet filter and a relatively new feature called 'IP sets' to create a high-performance index of the block lists.įor this to work, you'll need to make sure your kernel supports iptables and IP sets: CONFIG_IP_NF_IPTABLES=y Some other solutions exist, such as simple scripts that convert block lists into iptables rules, but depending on the size of the list, these would consume so many system resources it would be impossible to use the computer.įortunately, the Linux kernel itself actually includes all the capabilities necessary to implement a large blacklist as part of the netfilter framework. There are a few others, such as moblock and iplist that appear to have been dead for quite some time.

The documentation was also pretty terrible. The original PeerGuardian for Linux appears to have been revived, but when I tired to use it, it didn't work and was incredibly unstable. Unfortunately, there isn't a really good alternative for Linux. It blocks more traffic than one might expect, too.

suing people for sharing content, even legitimately), advertisements, malware, etc. It is commonly used to block parties that participate in anti-peer-to-peer activities (i.e. On Windows, PeerBlock is a firewall of sorts that blocks inbound and outbound communication with hosts based on their inclusion in one of several lists.

Free peerblock lists