Iptables command options
The Iptables command options are as follows.
-A: Appends the rule to the end of the specified chain. Unlike the -I option described below, it does not take an integer argument. It always appends the rule to the end of the specified chain.
-D <integer> | <rule>: Deletes a rule in a particular chain by number (such as 5 for the fifth rule in a chain), or by rule specification. The rule specification must exactly match an existing rule.