What does forward mean in linux

In Linux, "forward" refers to the transfer process of network data packets between different network interfaces. The enabling methods are: 1. Run sysctl -w net.ipv4.ip_forward=1 to temporarily enable IPv4 data Packet forwarding function; 2. Edit the "/etc/sysctl.co" file, add and save "net.ipv4.ip_forward =1" at the end of the file, and then use the "sysctl -p" command to reload the configuration file to enable permanent activation.

The operating system of this tutorial: Linux5.18.14 system, Dell G3 computer.

In Linux, "forward" usually refers to the process of transferring network data packets between different network interfaces. It is a network function used to forward packets from one network interface to another.

Specifically, in the network, when a data packet on a computer needs to be sent to the target address, after routing selection, if the target address is in the same subnet as the current host, the data The packet is sent directly to the target host. However, if the destination address is in a different subnet, a forwarding operation is required.

The forwarding of data packets is usually handled by network devices (such as routers, switches) or the network protocol stack of the operating system (such as the Linux kernel). In Linux, forwarding operations can be enabled or disabled by configuring kernel parameters. By enabling forwarding, the Linux host becomes a router and forwards received packets to the target network.

You can use one of the following methods to enable the forwarding function:

• Temporarily enable the forwarding function:

  Use the sysctl command and run sysctl -w net.ipv4 .ip_forward=1 temporarily enables the forwarding function of IPv4 data packets.

• Permanently turn on the forwarding function:

  Edit the /etc/sysctl.conf file, add net.ipv4.ip_forward = 1 at the end of the file, save and exit. Then use the sysctl -p command to reload the configuration file.

Note, when enabling forwarding, make sure to follow network security best practices and configure appropriate firewall rules to protect network security.

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