Find out Gateway / router IP address under Linux / UNIX using route command

You need to use route command. This command can manipulates the kernel’s IP routing tables. It can be also use to print gateway / router IP address. Type the following command to see default gateway:
$ route -n
Output:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.0.10.54      0.0.0.0         255.255.255.0   U     0      0        0 ra0
0.0.0.0         10.0.10.1       0.0.0.0         UG    0      0        0 ra0

192.168.1.1 is gateway IP address for our computer. The flag U indicates that route is up and G indicates that it is gateway. You can print gateway name, enter:
$ route
Output:

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.0.10.1    *               255.255.255.0   U     0      0        0 ra0
default         wrt             0.0.0.0         UG    0      0        0 ra0

Second column prints Gateway hostname / IP address. In our example wrt is gateway.

netstat command example to find out gateway/router IP

Open a terminal and type the following command:
# netstat -r -n
Sample outputs:

Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         10.0.10.1   0.0.0.0         UG        0 0          0 eth1
10.0.10.1     0.0.0.0         255.255.255.0   U         0 0          0 eth1