Linux static route settings

Article title: Introduction to static route settings in Linux. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.

Now there are five devices: PC1 connected to ROUT1, ROUT1 connected to ROUT2, ROUT2 connected to ROUT3, and ROUT3 connected to PC2. the topology is shown below:

□---- ○ ---- □

PC1 ROUT1 ROUT2 ROUT3 PC2

The static IP addresses of the five devices are:

PC1 192.168.1.88/24

ROUT1 192.168.1.128/24 192.168.2.128/24

ROUT2 192.168.2.66/24 192.168.3.66/24

ROUT3 192.168.3.100/24 192.168.4.33/24

PC2 192.168.4.66/24

The PC1 configuration is as follows:

# Ifconfig eth0 192.168.1.88 netmask 255.255.255.0

# Route add default gw 192.168.1.128

Configure ROUT1 as follows:

# Ifconfig eth0 192.168.1.128 netmask 255.255.255.0

# Ifconfig eth0: 1 192.168.2.128 netmask 255.255.255.0

# Route add-net 192.168.4.0/24 gw 192.168.2.66

Configure ROUT2 as follows:

# Ifconfig eth0 192.168.2.66 netmask 255.255.255.0

# Ifconfig eth0: 1 192.168.3.66 netmask 255.255.255.0

# Route add-net 192.168.1.0/24 gw 192.168.2.128

# Route add-net 192.168.4.0/24 gw 192.168.3.100

Configure ROUT3 as follows:

# Ifconfig eth0 192.168.3.100 netmask 255.255.255.0

# Ifconfig eth0: 1 192.168.4.33 netmask 255.255.255.0

# Route add-net 192.168.1.0/24 gw 192.168.3.66

The PC2 configuration is as follows:

# Ifconfig eth0 192.168.4.66 netmask 255.255.255.0

# Route add default gw 192.168.4.33

In this way, PC1 can ping PC2.

Note:

The above three routers are replaced by three PCs. To replace a router with a computer, you must enable the IP forwarding function of the computer. change the content in/proc/sys/net/ipv4/ip_forward to 1 (the default value is 0 ), run the following command to complete

# E cho 1>/proc/sys/net/ipv4/ip_forward

After the network is restarted, the above file is automatically changed to 0

Add several commands:

1. delete the default route

# Route del default

2. View routes

# Route-n

3. set a route entry for a specified CIDR block

# Route add-net 192.168.3.0 netmask 255.255.255.0 gw 192.168.6.66

Or

# Route add-net 192.168.3.0/24 gw 192.168.6.66

4. delete a route entry

# Route del-net 192.168.3.0 netmask 255.255.255.0

Or

# Route del-net 192.168.3.0/24

(T002)