networks

network configuration

• using ip $ ip a

• using ifconfig $ ifconfig

• using nmcli (networkmanager) $ nmcli device show

Enable/disable interfaces

• using ifdown e ifup # ifdown eth0 && ifup eth0

• using ip # ip link set dev eth0 down && ip link set dev eth0 up

• using networking (deprecated) # service networking restart

• using network restart # /etc/init.d/network restart

• using ifconfig # ifconfig eth0 down && ifconfig eth0 up

Setting persistent configuration

• sample ‌/etc/network/interfaces configuration

network 191.36.8.32
address 191.36.8.36
gateway 191.36.8.62
broadcast 191.36.8.63
netmask 255.255.255.224
dns-nameservers 191.36.8.2
dns-nameservers 191.36.8.3

• after changing, restart the interface (e.g. auto eth0 iface eth0 inet static)

scan devices

• using nmap $ sudo nmap -sn 192.168.0.0/24

using ip command

• show all interfaces configuration $ ip a

• add an ip to an interface (not persistent) $ ip a add 192.168.0.1/24 dev eth0

• Remove an ip from an interface $ ip a del 192.168.0.1/24 dev eth0

• deactivate an interface $ ip link set dev eth0 down

• activate an interface $ ip link set dev eth0 up

• modifying a MAC address of an interface (interface must be deactivated) $ ip link set dev eth0 address 00:0c:13:45:5b:b6

• add default route (default may be replaced by 0/0) $ ip route add default via 192.168.0.254

• add a static route to a subnetwork $ ip route add 10.0.0.0/24 via 192.168.0.254 dev eth0

useful tools

• ip calculator # ipcalc 191.36.8.36/27