ubuntu 底下 ufw 作 rate limit

大概就是

ufw limit proto tcp from any to 1.2.3.4 port 1234,2234

就會對本機 IP 1.2.3.4 的 port 1234,2234 做出 30 秒只能連線六次的限制。
然後不用預設的30/6的話就不用上面那條，直接是 allow 然後手動改 /etc/ufw/before.rules
在

# Don't delete these required lines, otherwise there will be errors
*filter
:ufw-before-input - [0:0]
:ufw-before-output - [0:0]
:ufw-before-forward - [0:0]
:ufw-not-local - [0:0]
# End required lines

之後加上

# Limit IP connection(s)
# Limit to 10 concurrent connections on port 80 per IP
#-A ufw-before-input -p tcp --syn --dport 80 -m connlimit --connlimit-above 300 -j DROP
# Limit to 20 connections on port 80 per 2 seconds per IP
#-A ufw-before-input -p tcp --dport 80 -i eth1 -m state --state NEW -m recent --set
#-A ufw-before-input -p tcp --dport 80 -i eth1 -m state --state NEW -m recent --update --seconds 1 --hitcount 20 -j DROP

更機車的設定可以參考這裡