Netfilter Performance Testing
https://people.netfilter.org/kadlec/nftest.pdfthe performance of Linux and netfilter at every major stage of packet filtering: plain routing, connection tracking, filtering and NAT. Two different hardware configurations were compared and performance dependency on the number of rules was examined using iptables, nf-hipac[2] and ipset[3] as well.
IP sets - Netfilter
https://ipset.netfilter.orgIP sets are a framework inside the Linux kernel, which can be administered by the ipset utility. Depending on the type, an IP set may store IP addresses, networks, (TCP/UDP) port numbers, MAC addresses, interface names or combinations of them in a way, which ensures lightning speed when matching an entry against a set.
ChangeLog - IP sets
https://ipset.netfilter.org/changelog.htmlIntroduce RCU in all set types instead of rwlock per set (performance tested by Jesper Dangaard Brouer) Remove rbtree from hash:net,iface in order to run under RCU Explicitly add padding elements to hash: net,net and ... ipset can now test IP addresses in nethash type of sets (i.e. addresses in netblocks added to the set) 2.2.0 ...