Systems connected to the network will generally access to the internet. In order to access to the internet they need some network configuration like gateway or default gateway. In this tutorial we will examine how to add or change default gateway in Ubuntu, Debian, CentOS, Fedora, Mint, Kali operating systems.
List Routing Table
Routing table is used to route IP network communication. Hosts generally uses default route to send packages which will redirect them accordingly to transmit destination. We will start by listing current routing table. We will use ip route show command like below.
$ ip route show
Our default gateway line is
default via 192.168.122.1 dev ens3
- default means this line is default gateway
- via 192.168.122.1 specifies next hop which is default gateway IP address
- dev ens3 is the interface we want use to access default gateway
Remove Existing Default Gateway
Removing default gateway is easy if we list routing table because routing table line is used with del command like below. But keep in mind if you are connecting system remotely from different network which means if you are using default route you connection will be lost.
$ ip route del default via 192.168.122.1 dev ens3
- ip route del is our key line which deletes specified default gateway
- default via 192.168.122.1 dev ens3 is the same as routing table
Add New Default Gateway
As stated previously default gateway is used to send packages in order to transmit to the destination. We can add new default gateway with the ip route add command like below.
$ ip route add default via 192.168.1.1 dev ens3
- ip route add will add provided default gateway
- default means target network is all which is default
- via 192.168.1.1 is our default gateway network address
- dev ens3 is network interface for default gateway
Check
List routing table again and ping some of remote networks will give the status of default gateway
$ ip route show default via 192.168.1.1 dev ens3 10.0.3.0/24 dev lxcbr0 proto kernel scope link src 10.0.3.1 192.168.122.0/24 dev ens3 proto kernel scope link src 192.168.122.211
How To Add or Change Default Route or Default Gateway in Ubuntu, Linux? Infografic
this is runtime only, and will not persist across reboots