a - ip command ip command is a tool for managing network tasks ip address → displays detailed information about all Network interfaces. ip link → displays link layer information ip link -s → displays link layer statistics ip neighbour → lists devices in the same network ip route → displays routing table Other objects: neighbour → ARP or NDISC cache entry rule → Rule in routing policy database. tunnel → tunnel over IP maddress → Multicast address
b - ip command examples ip addr add 192.168.1.2/24 dev eth0 → sets to eth0 interface specific IP and subnet mask ip route add default via 192.168.1.1 dev eth0 → sets new default gateway ip addr del 192.168.1.100/24 dev eth0 → deletes specific IP address sudo ip route flush → flushes routing tables sudo ip neighbor flush → flushes neighbour entries ip rule show → show IP rules ip rule add priority 1000 from 192.168.1.0/24 to 10.0.0.0/8 table main → example of adding new rule
c - netstat command netstat displays network related statistics and connections It provides various options to filter, sort, display or modify network-related data netstat -tulpn → shows all listening (LISTEN) TCP connections netstat -nr → shows the routing table netstat -tna | grep :25 → checks network connections on a specific port sudo netstat -tcp → lists all established TCP connections sudo netstat --statistics → shows network statistics netstat -au → lists all UDP ports netstat -l → lists all listening ports