Linux Connectivity

6 Jun 2022, 9:29 p.m.

19 Apr 2022, 9:39 p.m.

02:28 minutes

Networking

A look at various commands that can be used for configuring Linux network connectivity.

View IP Addresses

ifconfig
ip a

Adding or Deleting an IP Address

ifconfig

ifconfig eth0 add 192.168.80.174
ifconfig eth0 del 192.168.80.174

ip a add 192.168.80.174 dev eth0
ip a del 192.168.80.174 dev eth0

static interface configurations (\etc\network\interfaces).

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static u
address 192.168.20.9
netmask 255.255.255.0
gateway 192.0.2.254

ifconfig

ifconfig eth0 hw ether 00:0c:29:33:4e:aa

ip link set dev eth0 address 00:0c:29:33:4e:aa

ifconfig

ifconfig eth0 down
ifconfig eth0 up

ip link set dev eth0 down
ip link set dev eth0 up

ifconfig

ifconfig eth0 arp
ifconfig eth0 -arp

ip link set dev eth0 arp on
ip link set dev eth0 arp off

route

route add default gw <ip>
route add -net 192.168.10.0 netmask 255.255.255.0 dev eth0
route

ip route add default via <gw addr>
ip route add <ip> via <gw addr> dev <interface>
ip route show

Request IP Address (Sends broadcast)

dhclient

More advanced request, forces IPv4, against the specified server for the specified interface

dhclient -4 -s 10.128.128.128 eth0

Check if 8021q is loaded:

lsmod | grep 8021q

If not:

modprobe 8021q

Add vConfig

vconfig add eth0 5

Check:

ifconfig eth0.5

ifconfig eth0.5 192.168.1.100 netmask 255.255.255.0 broadcast 192.168.1.255 up
ifconfig eth0.5 x.x.x.x netmask x.x.x.x broadcast x.x.x.x up

To delete:

ifconfig eth0.5 down
vconfig rem eth0.5

OR:

ip link add link eth0 name eth0.5 type vlan id 5
ip link
ip -d link show eth0.5

You need to activate and add an IP address to vlan link, type:

ip addr add 192.168.1.200\24 brd 192.168.1.255 dev eth0.5
ip link set dev eth0.5 up

To remove:

ip link set dev eth0.5 down
ip link delete eth0.5