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clearing_iptables [2023/05/08 04:37] – -grammar-intro hogwildclearing_iptables [2024/10/31 21:09] (current) hogwild
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 ===== Clearing iptables custom commands prior to applying new ones ===== ===== Clearing iptables custom commands prior to applying new ones =====
  
-Let's say, as an example, that you wanted to use some custom iptables commands in a script, such as the firewall script. In fact, the following principles would apply to any recurring script (such as WAN Up).+As an example, let's say that you wanted to use some custom iptables commands in a script, such as the firewall script. (Actually, the following principles would apply to any recurring scriptsuch as "WAN Up").
  
  \\ You can remove previously-added iptables directives using a simple approach:  \\ You can remove previously-added iptables directives using a simple approach:
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  \\  \\
  
-The commands below will check what iptables **-A** (append) or **-I** (insert) directives have been issued previously in the current Script/Firewall text. They will then force a run of the same command, replacing any instance of **-A** or **-I** with a **-D** (Delete) switch/parameterEssentially this will essentially reverse/remove any user-added iptables directives. It should be noted that, a user might have created custom tables in which to use advanced iptables commands. This is usually achieved via the "**-N**" (new) switch/parameter. The same principles described above will apply to previous usage of the **-N switch/parameter**.+The commands below will check what iptables **-A** (append) or **-I** (insert) directives have been issued previously in the current Script/Firewall text. They will then force a run of the same command, replacing any instance of **-A** or **-I** with a **-D** (Delete) commandIn essence, this will reverse/remove any previous user-added iptables directives.
  
- \\ Here are some things to remember when considering these commands:+You might have created custom tables in which to use advanced iptables commands. This is usually performed using the "**-N**" (new) command. The same principles described above will also apply to previously-issued directives which used the **-N command**.
  
-  * First, you need to dereference the custom table from the built-in one first (using the above approach)+ \\ Here are a few rules to remember when using these commands: 
-  * A table must then be emptied with the **-F** (Flush) switch/parameter first (for example**iptables -F $TABLE_NAME ) **. + 
-  * Only at this point will you be allowed to remove the table with the command:  **iptables -X $TABLE_NAME** .+ \\ 
 + 
 +  * First, you need to dereference the custom table from the built-in one, \\ using the above method
 +  * A table must then be emptied with the **-F** (Flush) switch/parameter \\ (for example: "**iptables -F $TABLE_NAME") **. 
 +  * Only then will you be allowed to remove the table by using the command: \\ "**iptables -X $TABLE_NAME"**. 
 + 
 + \\
  
  
clearing_iptables.1683517059.txt.gz · Last modified: 2023/05/08 04:37 by hogwild