In this tutorial, you will learn how to configure network in Debian to use static IP addresses and DHCP. You will also learn how to configure the DNS name servers, Gateways, and subnets.
This tutorial covers the following versions of Debian:
- Debian 8 Jessie
- Debian 9 Stretch
- Debian 10 Buster
Network Interfaces Files
Debian’s network interfaces can be configured in two places. The primary location for network configurations is in the
The second location for network configurations is under
/etc/networks/interfaces.d, where you can drop network config files rather than storing everything in the
/etc/networks/interfaces file looks like the following.
# This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). source /etc/network/interfaces.d/* # The loopback network interface auto lo iface lo inet loopback # The primary network interface allow-hotplug enp0s3 iface enp0s3 inet dhcp
The first thing the
interfaces file does it load additional configuration files from
/etc/network/interfaces.d, if any files are stored there. It then proceeds to load network configurations from defined below that line.
Setting a Static IP address
To set a static IP address for an interface named
enp0s3, you would write the following configuration.
iface enp0s3 inet static address 192.168.1.2/24 gateway 18.104.22.168
The configuration above does the following:
- static sets the interface as static
- address sets the IP address to 192.168.1.2 and its subnet using CIDR /24, or subnet 255.255.255.0.
- gateway sets the network gateway IP address for routing traffic outside of the interface’s subnet.
This configuration can be added to the
interfaces file or written to a configuration file under
For example, the file could be saved as
To apply your new network settings you will need to bring the interface down and then back up again.
- Bring the interface you just updated down.
- Bring the interface back online.
Verify your network settings are applied correctly. For Debian 10 and Debian 9, you can use the
ip a command. For Debian 8 you would use the
Setting a DHCP Address
A DHCP address is configured as shown in the example below. Unlike the the static IP address it’s a one-liner, as we do not need to set an address or gateway. These values will automatically be assigned by your network.
iface enp0s3 inet dhcp
Applying New Network Settings
To apply your new network settings you will need to bring the interface offline and then back online.
- Bring the interface down.
- Bring the interface back online
Verifying network settings in Debian 9 and Debian 10
With Debian 9 and Debian 10 you must use the
ip command to view the current state of your network interfaces.
mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 08:00:27:de:14:99 brd ff:ff:ff:ff:ff:ff inet 10.0.0.41/24 brd 10.0.0.255 scope global dynamic enp0s3 valid_lft 562759sec preferred_lft 562759sec inet6 2607:fea8:4de0:b900:a00:27ff:fede:1499/64 scope global dynamic mngtmpaddr valid_lft 298sec preferred_lft 298sec inet6 fe80::a00:27ff:fede:1499/64 scope link valid_lft forever preferred_lft forever
In the output of the
ip a command we can see that our interface, enp0s3, is in an UP state, has been assigned IP address 10.0.0.41/24. If you set your IP address to 10.0.0.41/24, then your changes have been applied successfully.
Verifying network settings in Debian 8
Network interfaces states can be check in Debian 8 using the
lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:8 errors:0 dropped:0 overruns:0 frame:0 TX packets:8 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:480 (480.0 b) TX bytes:480 (480.0 b) p2p1 Link encap:Ethernet HWaddr 00:1C:C0:AE:B5:E6 inet addr:192.168.0.1 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::21c:c0ff:feae:b5e6/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:41620 errors:0 dropped:0 overruns:0 frame:0 TX packets:40231 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:21601203 (20.6 MiB) TX bytes:6145876 (5.8 MiB) Interrupt:21 Base address:0xe000