Explanation of the output information of the route command in Linux

Using the route command without any parameters will display a real route table, and the output may be as follows:

Kernel IP routing table

Destination Gateway Genmask Flage Metric Ref Use Iface

192.168.100.0*255.255.255.0 U 0 0 0 etn0

127.0.0.0*255.255.255.0 U 0 0 0 l0

Default 192.168.100.5 0.0.0.0 UG 0 0 0 eth0

The output on this host consists of three rows in the header and below ):

The first line shows where the network traffic destined for 192.168.100.0 is associated with the eth0 device.

The second line shows where the network traffic destined for 127.0.0.1localhost or the IP address of the self-contained network device is sent.

The third line shows where the above two types of data are sent. Because the system does not know how to reach the Sending address of these data packets, these data packets must go through the gateway.

Let's take a look at the columns output by the route command:

Destination: The network range used by route table entries. If the destination address of an IP packet is a part of the network in a row output by route, this entry is used to route the packet.

Gateway: A host that accepts data packets sent to a specified Destination. Because the output is from a host rather than a computer as a dedicated router), the routing field can be asterisk *) or the default gateway; asterisks indicate that Destination is in the network to which the host belongs, so no route is required.) The default gateway refers to a specified IP address that sends all non-local traffic.

Flags: A 9-letter flag, indicating the information of route table entries. The u table indicates that the route is started. G indicates that the route points to the Gateway. Most other labels can be found in the online help manual of the route command by entering manroute, indicates how a route is created and updated through the routing daemon.

Metric: Number of routers required to reach the specified network.

Ref: The number of times this route is referenced. It is not used in the Linux kernel.

Use: the number of times the router is searched by the routing software. You can roughly estimate the network traffic to the specified network address.

Iface: indicates the destination address. It specifies the network excuse for the network packet to be sent.