A gateway is a node or a router that allows two or more hosts with different IP addresses to communicate with each other when connected to the same router. Without gateway, devices connected on the same router won’t be able to communicate with each other. To put this another way, the gateway acts as an access point to pass network data from a local network to a remote network. In this guide, we will see all the possible ways to find default gateway in Linux and Unix from commandline.
Table of Contents
Find Default Gateway In Linux
There are various commandline tools are available to view the gateway IP address in Linux. The most commonly used tools are: ip, ss, and netcat. We will see how check the default gateway using each tool with examples.
1. Find Default Gateway Using ip Command
The ip
command is used to show and manipulate routing, network devices, interfaces and tunnels in Linux.
To find the default gateway or Router IP address, simply run:
$ ip route
Or,
$ ip r
Or,
$ ip route show
Sample output:
default via 192.168.1.101 dev eth0 proto static metric 100 172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown 192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.20 metric 100
Did you see the line "default via 192.168.1.101" in the above output? This is the default gateway. So my default gateway is 192.168.1.101.
You can use -4
with ip route
command to display the IPv4 gateway only:
$ ip -4 route
And, use -6
to display the IPv6 gateway only:
$ ip -6 route
As you noticed in the output, the IP address and the subnet details are also shown. If you want to display ONLY the default gateway and exclude all other details from the output, you can use awk
command with ip route
like below.
To find the default gateway IP address using ip route
and grep
, run:
To print Gateway IP address with ip route
and awk
commands, run:
$ ip route | awk '/^default/{print $3}'
Or,
$ ip route show default | awk '{print $3}'
This will list only the gateway.
Sample output:
192.168.1.101
You can also use grep command with ip route
to filter the default gateway.
$ ip route | grep default default via 192.168.1.101 dev eth0 proto static metric 100
The ip route
is the recommended command to find the default gateway IP address in latest Linux distributions. However, some of you may still be using the legacy tools like route
and netstat
. Old habits die hard, right? The following sections explains how to determine the gateway in Linux using route
and netstat
commands.
2. Display Default Gateway IP Address Using route Command
The route
command is used to show and manipulate routing table in older Linux distributions, for example RHEL 6, CentOS 6.
If you're using those older Linux distributions, you can use the route
command to display the default gateway.
Please note that the route
tool is deprecated and replaced with ip route
command in the latest Linux distributions. If you still want to use route
for any reason, you need to install it.
First, we need to check which package provides route
command. To do so, run the following command on your RHEL-based system:
$ dnf provides route
Sample output:
net-tools-2.0-0.52.20160912git.el8.x86_64 : Basic networking tools Repo : @System Matched from: Filename : /usr/sbin/route net-tools-2.0-0.52.20160912git.el8.x86_64 : Basic networking tools Repo : baseos Matched from: Filename : /usr/sbin/route
As you can see in the above output, the net-tools package provides the route
command. So, let us install it using command:
$ sudo dnf install net-tools
Now, run route
command with -n
flag to display the gateway IP address or router IP address in your Linux system:
$ route -n
Sample output:
Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.1.101 0.0.0.0 UG 100 0 0 eth0 172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0 192.168.1.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
As you see in the above output, the gateway IP address is 192.168.1.101. You will also see the two letters "UG" under Flags section. The letter "U" indicates the interface is UP and G stands for Gateway.
3. View Gateway IP Address Using netstat Command
Netstat prints information about the Linux networking subsystem. Using netstat tool, we can print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships in Linux and Unix systems.
Netstat is part of net-tools package, so make sure you've installed it in your Linux system. The following commands install net-tools package in RHEL-based systems:
$ sudo dnf install net-tools
To print the default gateway IP address using netstat
command, run:
$ netstat -rn
Sample output:
Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 0.0.0.0 192.168.1.101 0.0.0.0 UG 0 0 0 eth0 172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0 192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
The netstat
command's output is same as route
command's output. As per the above output, the gateway IP address is 192.168.1.101 and the UG stands the NIC associated to gateway is UP and G indicates Gateway,
Please note that netstat
is also deprecated and it is recommended to use "ss
" command instead of netstat.
4. Print Default Gateway IP Address Or Router IP Address Using routel Command
The routel is a script to list routes with pretty output format. The routel script will list routes in a format that some might consider easier to interpret then the ip route
list equivalent.
The routel script is also the part of net-tools package.
To print the default gateway or router IP address, run routel script without any flags like below:
$ routel
Sample output:
target gateway source proto scope dev tbl default 192.168.1.101 static eth0 172.17.0.0/ 16 172.17.0.1 kernel linkdocker0 192.168.1.0/ 24 192.168.1.20 kernel link eth0 127.0.0.0/ 8 local 127.0.0.1 kernel host lo local 127.0.0.1 local 127.0.0.1 kernel host lo local 127.255.255.255 broadcast 127.0.0.1 kernel link lo local 172.17.0.1 local 172.17.0.1 kernel hostdocker0 local 172.17.255.255 broadcast 172.17.0.1 kernel linkdocker0 local 192.168.1.20 local 192.168.1.20 kernel host eth0 local 192.168.1.255 broadcast 192.168.1.20 kernel link eth0 local ::1 kernel lo ::/ 96 unreachable lo ::ffff:0.0.0.0/ 96 unreachable lo 2002:a00::/ 24 unreachable lo 2002:7f00::/ 24 unreachable lo 2002:a9fe::/ 32 unreachable lo 2002:ac10::/ 28 unreachable lo 2002:c0a8::/ 32 unreachable lo 2002:e000::/ 19 unreachable lo 3ffe:ffff::/ 32 unreachable lo fe80::/ 64 kernel eth0 ::1 local kernel lo local fe80::d085:cff:fec7:c1c3 local kernel eth0 local
To print only the default gateway, run routel with grep
like below:
$ routel | grep default default 192.168.1.101 static eth0
5. Find Gateway From Ethernet Configuration Files
If you have configured static IP address in your Linux or Unix system, you can view the default gateway or router IP address by looking at the network configuration files.
In RPM-based systems like Fedora, RHEL, CentOS, AlmaLinux and Rocky Linux, the network interface card (shortly NIC) configuration are stored under /etc/sysconfig/network-scripts/
directory.
Find the name of the network card:
# ip link show
Sample output:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0@if5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000 link/ether d2:85:0c:c7:c1:c3 brd ff:ff:ff:ff:ff:ff link-netnsid 0
The network card name is eth0. So let us open the network card configuration of this NIC card file:
# cat /etc/sysconfig/network-scripts/ifcfg-eth0
Sample output:
DEVICE=eth0 ONBOOT=yes UUID=eb6b6a7c-37f5-11ed-a59a-a0e70bdf3dfb BOOTPROTO=none IPADDR=192.168.1.20 NETMASK=255.255.255.0 GATEWAY=192.168.1.101 DNS1=8.8.8.8
As you see above, the gateway IP is 192.168.1.101
.
In Debian, Ubuntu and its derivatives, all network configuration files are stored under /etc/network/
directory.
$ cat /etc/network/interfaces
Sample output:
auto ens18 iface ens18 inet static address 192.168.1.150 netmask 255.255.255.0 gateway 192.168.1.101 dns-nameservers 8.8.8.8
Please note that this method should work only if the IP address is configured manually. For DHCP-enabled network, you need to follow the previous 4 methods.
Conclusion
In this guide, we listed 5 different ways to find default gateway in Linux and Unix operating systems. We also have included sample commands to display the gateway/router IP address in each method. Hope this helps.