iptables如何删除一条规则?

答:iptables -D <链> <要删除的某行>

1. 查看规则
$ sudo iptables -nvL --line-number
...
Chain FORWARD (policy DROP 0 packets, 0 bytes)
num   pkts bytes target     prot opt in     out     source               destination
...
8      4  193 reject     all  --  *      *       0.0.0.0/0            0.0.0.0/0            
9      48  1932 ACCEPT     all  --  *      *       0.0.0.0/0            0.0.0.0/0           
...
2. 删除某个规则(以上的规则"8      4  193 reject     all  --  *      *       0.0.0.0/0            0.0.0.0/0")

$ sudo iptables -D FORWARD 8