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Editor to share with you how Linux uses iptables to restrict multiple IP access to your server. I believe most people don't know much about it, so share this article for your reference. I hope you can learn a lot after reading this article. Let's learn about it together.

Preface

On the Linux kernel, netfilter is a subsystem responsible for packet filtering, network address translation (NAT), and protocol type-based connection tracking. This subsystem consists of packet filtering tables that contain the set of rules that the kernel uses to control packet filtering. Iptables is a tool for managing netfilter.

Multiple consecutive IP operations

1. Split into multiple commands to run

Iptables-An INPUT 192.168.122.2-j ACCEPT iptables-An INPUT 192.168.122.3-j ACCEPT iptables-An INPUT 192.168.122.4-j ACCEPT iptables-An INPUT 192.168.122.5-j ACCEPT.

This approach requires a lot of commands to be written, and results in long, unmanageable tables in iptables, and a small (negligible) impact on performance.

2. Access control to the IP of an IP segment, which can be controlled according to the form of IP/MASK

Iptables-An INPUT 192.168.122.0 Universe 24-j ACCEPT

This method needs to calculate the specified source code for the IP range, which is not flexible. (although many users use this method for convenience, there are security risks if there is too much authorization.)

3. Iptables has many modules, among which iprange is used to deal with the access control of continuous IP segments.

Iptables-An INPUT-m iprange-- src-range 192.168.122.2-192.168.122.34-j ACCEPT # match source IPiptables-An INPUT-m iprange-- dest-range 8.8.8.2-8.8.8.22-j DROP # match destination IP

This method is more flexible, there is no need to calculate what the mask is, just give the range.

The above is all the content of the article "how Linux uses iptables to restrict multiple IP access to your server". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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