Linux & Windows Tips, Tutorials, , Ideas

Forward a TCP port to another IP or port using NAT with Iptables

Forward a TCP port to another IP or port using NAT with Iptables

Besides using NAT for accessing the internet with multiple machines using a single IP address, there are many other uses of NAT. One of them is to forward all traffic that is sent to a certain TCP port to another host. In practice, this technique can be used to test a service on a new host without adjusting anything on the client. The users or the clients do not need to be pointed to a new machine in order to test it. When the test would be unsuccessful, removing the NAT-rule is all it takes to switch back.

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Block Port With IPtables

Block Port With IPtables

linux1.pro-east4serv-linux

How do I block port number with iptables under Linux operating systems?

Port numbers which are recognized by Internet and other network protocols, enabling the computer to interact with others. Each Linux server has a port number (see /etc/services file). For example:

 

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Linux: 20 Iptables Examples For New SysAdmins

Linux: 20 Iptables Examples For New SysAdmins

 netfilter is a set of hooks inside the Linux kernel that allows kernel modules to register callback functions with the network stack. A registered callback function is then called back for every packet that traverses the respective hook within the network stack.

This Linux based firewall is controlled by the program called iptables to handles filtering for IPv4, and ip6tables handles filtering for IPv6. I strongly recommend that you first read ourquick tutorial that explains how to configure a hostbased firewall called Netfilter (iptables) under CentOS / RHEL / Fedora / Redhat Enterprise Linux. This post lists most simple iptables solutions required by a new Linux user to secure his or her Linux operating system from intruders.

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Linux Iptables Limit the number of incoming tcp connection / syn-flood attacks

Linux Iptables Limit the number of incoming tcp connection / syn-flood attacks

A SYN flood is a form of denial-of-service attack in which an attacker sends a succession of SYN requests to a target’s system. This is a well known type of attack and is generally not effective against modern networks. It works if a server allocates resources after receiving a SYN, but before it has receivedRead more about Linux Iptables Limit the number of incoming tcp connection / syn-flood attacks[…]

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Best quick forword visitors from old server to new server

Best quick forword visitors from old server to new server

Hey guys ! I will explain the best way forword all visitor to the new server quickly step 1 : set net.ipv4.ip_forward > 1 # nano /etc/sysctl.conf # replace net.ipv4.ip_forward=0 to net.ipv4.ip_forward=1 # save file . # sysctl -p step 2 : Then, we will add a rule telling to forward the traffic on portRead more about Best quick forword visitors from old server to new server[…]

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