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This article mainly shows you "how to configure static routing under Linux". The content is simple and clear. I hope it can help you solve your doubts. Let me lead you to study and learn this article "how to configure static routing under Linux".

A static route is a form of routing in which routing items are manually configured rather than dynamically determined. Unlike dynamic routes, static routes are fixed and will not change, even if the network condition has changed or has been reconfigured.

Background and principle

The function of the router is to realize the communication between one network segment and another, and the routing is divided into static route, dynamic route,

Default routes and directly connected routes. Static routes are specified manually, and the advantage of using static routes is the high security and confidentiality of the network. Dynamic routing requires routers to exchange their routing tables frequently, and the analysis of routing tables can reveal information such as network topology and network address. Therefore, static routing can also be used in the network for security reasons. Does not consume network bandwidth because static routes do not generate update traffic.

Network planning simulation

The simulation uses four Linux machines, named Linux1, Linux2 (router1) and Linux3 (router).

And Linux4, where Linux2 and Linux3 are configured as routers to configure static routing functions, using different network segments and network modes for communication between each two machines

Environmental simulation

Clone four Linux machines and name them. Configure the network card of each machine according to the network plan diagram, using only static ip and subnet mask. The cloned machine needs to execute the command > / etc/udev/rules.d/70-persistent-net.rules to clear the relevant information files of the network card. After configuration, check the ip and verify the communication with the network segment devices.

Linux1

Linux2

Linux3

Linux4

Configure static rout

4.1 add static routes:

Common parameters:

Add adds routing

Del delete route

-net sets the route to a network segment

-host sets the route to a host

Gw egress Gateway IP address

Dev egress Gateway physical device name

Step 1

Linux1:route add-net 192.168.1.0 gw 24 gw 10.0.0.129 (from 1 to 3)

Linux3:route add-net 10.0.0.0 amp 24 gw 192.168.1.129 (from 3 to 1)

At this point, Linux1 and Linux3 can communicate with each other through ping

Step 2

Linux4:route add-net 192.168.1.0 Linux4:route add 24 gw 192.168.2.130 (from 4 to 2)

Linux2:route add-net 192.168.2.0ax 24 gw 192.168.1.130 (from 2 to 4)

At this point, Linux2 and Linux4 can communicate with each other through ping

Step 3:

Linux1:route add-net 192.168.2.0ax 24 gw 10.0.0.129 (from 1 to 4)

Linux4:route add-net 10.0.0.0 amp 24 gw 192.168.2.130 (from 4 to 1)

At this point, Linux1, Linux2, Linux3 and Linux4 can communicate with each other

4.2 if Linux2 and Linux3 machines are involved in configuration, kernel forwarding should be enabled.

Echo 'net.ipv4.ip_forward = 1' > > / etc/sysctl.conf

Or vi / etc/sysctl.conf-> net.ipv4.ip_forward=1

Sysctl-p loads the sysctl configuration file

Verify static rout

5.1 View the routing tables of their respective machines

5.2 execute the ping command on the Linux1 machine to communicate in pairs

5.3 use tcpdump to crawl icmp packets between each pair of communication on other machines for verification

Ping 10.0.0.129-c3

Ping 192.168.1.130-c3

Ping 192.168.2.131-c3

The above configuration will fail when restarting the network service or restarting the system. If you want to take effect permanently, there are several ways

Method

Take Linux1 as an example

Method 1: use route-eth0 file

Vi / etc/sysconfig/network-scripts/route-eth0 # does not exist by default and needs to be created manually

Add the following

192.168.1.0/24 via 10.0.0.129

192.168.2.0/24 via 10.0.0.129

# when there are two network cards, the principle for configuring the route is that the network segment where the network card is located is the route exit

# write to the configuration, restart the network service and restart the system will take effect

Method 2: use static-route file

Vi / etc/sysconfig/static-routes # does not exist by default and needs to be created manually

Add the following

Any net 192.168.1.0/24 gw 10.0.0.129

Any net 192.168.2.0/24 gw 10.0.0.129

# write to the configuration, restart the network service and restart the system will take effect

Method 3: use rc.local file

Vi / etc/rc.local

Add the following

Route add-net 192.168.1.0 Universe 24 gw 10.0.0.129

Route add-net 192.168.2.0 bank 24 gw 10.0.0.129

# write it to the configuration and restart the system will take effect

These are all the contents of the article "how to configure static routing under Linux". 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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