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Although the Linux operating system has many advantages, their safety is also high, but you should not resulting into a false sense of security, because the security of your Linux system still might be compromised. Now let us look at how to use the IP chain (IPchains) to create Linux system firewall to protect your system from damage.
Assume you already have some basic knowledge about the Internet. It should be said, familiar as IP address, type TCP port and network transmission of data, the vocabulary is very useful. To have a general understanding of the firewall is very necessary.
Command:
We need to establish a set of rules from such chains to enter the IP network path coming and going. Each rule is placed in one of the three chains, three chains are: Chain store input data input, storage and output chain transmission chain output data.
Each additional rule, we must start from the IP chain, and to add some or all of the following steps. Additional (Append), delete (Delete), insert (Insert) and replacement (Replace), these commands are usually followed after the initial IP chains command and directs the program should be added to the rules on which the command chain and how to add . Added to -A, -D, -I, or -R start, plus the name behind these chain letters (input or output chain chain).
When you want to use the Insert command, must be added to the command position, behind the chain name specific line numbers.
When you use the Replace command, you need to specify the line number to be replaced, use the Delete command, you must also specify the number of rows to be deleted.
When you use the Delete option, and then enter the number behind the line without any other content. As long as you type ipchains -L, you can find the role of command line number. |
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