Networking¶

Ubuntu Server uses Netplan for network configuration with systemd-networkd as the default renderer.

Comprehensive Netplan Guide

For in-depth Netplan coverage including bridges, bonds, VLANs, and advanced routing, see the Netplan Configuration Guide.

Quick Configuration¶

Basic Static IP¶

Edit /etc/netplan/00-installer-config.yaml:

network:
  version: 2
  renderer: networkd
  ethernets:
    enp5s0:
      addresses:
        - 192.168.1.100/24
      routes:
        - to: default
          via: 192.168.1.1
      nameservers:
        addresses:
          - 1.1.1.1
          - 8.8.8.8

DHCP Configuration¶

network:
  version: 2
  renderer: networkd
  ethernets:
    enp5s0:
      dhcp4: true

Apply Configuration¶

# Test configuration (reverts after 2 minutes if no confirmation)
sudo netplan try

# Apply configuration
sudo netplan apply

Verification¶

# Check IP addresses
ip addr show

# Check routes
ip route show

# Check DNS
resolvectl status

# Test connectivity
ping -c 3 8.8.8.8
ping -c 3 google.com

Interface Naming¶

Find your interface name:

ip link show

Common patterns:

Pattern	Description
`enp5s0`	PCI Ethernet
`eno1`	Onboard Ethernet
`ens192`	Hotplug slot
`eth0`	Legacy naming (rare)

Common Tasks¶

Multiple IP Addresses¶

network:
  ethernets:
    enp5s0:
      addresses:
        - 192.168.1.100/24
        - 192.168.1.101/24

Multiple DNS Servers¶

network:
  ethernets:
    enp5s0:
      nameservers:
        addresses:
          - 1.1.1.1
          - 8.8.8.8
          - 9.9.9.9
        search:
          - example.com

Static Routes¶

network:
  ethernets:
    enp5s0:
      routes:
        - to: default
          via: 192.168.1.1
        - to: 10.0.0.0/8
          via: 192.168.1.254

Troubleshooting¶

Configuration Issues¶

# Check syntax
sudo netplan generate

# Debug apply
sudo netplan --debug apply

Common Problems¶

Problem	Solution
No IP address	Check DHCP server or static config
Can't reach gateway	Check cable, subnet mask, gateway IP
DNS not working	Check nameservers configuration
Routes wrong	Verify routes section in netplan

Reset Network¶

# Restart networking
sudo systemctl restart systemd-networkd

# Or reapply netplan
sudo netplan apply

Security Considerations¶

Netplan manages network configuration, not security. For network security:

See Firewall for UFW configuration
See Firewall & Security Guide for comprehensive firewall coverage

Topic	Location
Full Netplan Guide	Netplan Configuration
Bridges	Netplan Bridges
VLANs	Netplan VLANs
Firewall	Firewall Guide