NETS1028
Firewalls and Filters related links
NetfilterHome
iptables-extensions, or, the joy of being the man in the middle
iptables-persistent package info to make Ubuntu behave like Redhat
kernel parameters
Old but still valid discussion of several kernel tuning parameters
Kernel tuning for disk caching example
Tuning network buffering for bandwidth delay products example
iptstate homepage
UFW
Gufw
Ubuntu sectools list including iptables frontends
ipkungfu frontend for iptables
fail2ban
fail2ban video from lightning talks
Discussion about the future of iptables vs. nftables and bpfilter
Single Packet Authentication
Nftables - Netfilter and VPN/IPsec packet flow