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clearing_iptables [2023/05/08 04:30] – -grammar, condense bulleted points at bottom hogwildclearing_iptables [2023/05/08 04:49] (current) – added "previous" hogwild
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-===== Clearing iptables custom commands prior to re-applying new ones =====+===== Clearing iptables custom commands prior to applying new ones =====
  
-Let's say, for example, you wanted to use some custom iptables commands in a script, such as the firewall script. Actually, the following examples could apply to any recurring script (such as WAN Up).+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").
  
- \\ + \\ You can remove previously-added iptables directives using a simple approach:
- +
-You can remove what previously added iptables directive with a simple approach:+
  
  \\  \\
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  \\  \\
  
-This command here below will check what iptables **-A** (append) or **-I** (insert) have been used in the current Script/Firewall text area and force a run of the same command replacing any **-A** or **-I** with a **-D** (Delete). This will essentially 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. You can apply the same principles above to 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 commandreplacing any instance of **-A** or **-I** with a **-D** (Delete) commandIn essence, this will reverse/remove any previous user-added iptables directives.
  
- \\+A user 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**.
  
-Remember that:+ \\ Here are some rules to remember when using these commands:
  
-  * You need to first dereference the custom table from the built-in one first (using the above approach)+  * First, you need to dereference the custom table from the built-in oneusing the above method
-  * A table must then be emptied with the **-F** (Flush) switch/parameter first (for example, **iptables -F $TABLE_NAME ) **.+  * A table must then be emptied with the **-F** (Flush) switch/parameter (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** .   * Only at this point will you be allowed to remove the table with the command:  **iptables -X $TABLE_NAME** .
 +
 + \\
  
  
clearing_iptables.1683516613.txt.gz · Last modified: 2023/05/08 04:30 by hogwild