Understanding Routing table entry

Question

I want to ask a question about route command in Linux. I have enter following command in Linux terminal

> route

and got the output:

Answer 1

Let's go through the lines one by one:

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.1.0     *               255.255.255.0   U     1      0        0 eth0

This says that any packet with a destination of 192.168.1.0 through 192.168.1.255 will be sent out eth0 without using a gateway (unless a more-specific route overrides this one).

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.122.0   *               255.255.255.0   U     0      0        0 virbr0

This says that any packet with a destination of 192.168.122.0 through 192.168.122.255 will be sent out virbr0 without using a gateway. (Again, unless a more-specific route overrides this one.)

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
link-local      *               255.255.0.0     U     1000   0        0 eth0

This says that any packet with a link-local address will be sent out interface eth0 with no gateway.

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.1.1     0.0.0.0         UG    0      0        0 eth0

This says that any packet to a destination without another route will be sent out eth0, using 192.168.1.1 as a gateway.