To understand a Linux system’s network configuration, check its addresses, routes, DNS settings, and listening services. Older commands such as ifconfig and route still appear in historical documentation, but the ip command is preferred on modern systems.
IP addresses and interfaces
ip addr ip link
Routes and default gateway
ip route
DNS configuration
cat /etc/resolv.conf resolvectl status
On systems using systemd-resolved, /etc/resolv.conf may be generated automatically, so resolvectl status can provide more useful detail.
Listening ports
ss -tulpn
Together, these commands give a quick picture of how the host is connected and how traffic leaves the system.