OpenWrt 22.03 open-source Linux operating system for routers and entry-level embedded devices has just been released with over 3800 commits since the release of OpenWrt 21.02 nearly exactly one year ago.
Today I will show you the iptables rules I set on my main personal computer, with detailed comments about why I came to use these rules after several years of Linux desktop usage. The rules I use now have been simplified as much as I could and are based on common rules and advice that can be found on the network and also on input I got from experienced network administrators. I
Fred Stluka from Bristle.com just introduced me to port knocking -- a method of opening ports on a firewall by trying to connect with a series of ports in a pre-determined order. The sequence of "knocks" acts like a secret access code -- like tapping out the first couple of bars from your favorite song to tell someone inside that it's you.
ow do I restrict the number of connections used by a single IP address to my server for port 80 and 25 using iptables?
You need to use the connlimit modules which allows you to restrict the number of parallel TCP connections to a server per client IP address (or address block).
This is useful to protect your server or vps box against flooding, spamming or content scraping.