network setup with iproute2 and net-tools commands

In Linux, the network setup of a machine is done with the iproute2 tools. The iproute tools supersede the now obsolete net-tools, which include, among others, the well known ifconfig, route and netstat commands.

The commands of iproute2 tools are:

• ip – configure and manage interfaces (devices) and routing tables.
• tc – configure and manage traffic control rules.
• bridge – manage bridge devices.
• arpd – manage the ARP cache.
• ss – provides network information, i.e. about TCP and UDP sockets.

The table below list the most important iproute2 commands to set up a network and display its configuration. For each iproute2 command, the corresponding net-tools command is listed.

For each iproute2 command in the table above, there is also a short form, which I didn’t include. I tend to use the long forms, because I find them easier to remember. man ip and man ss are your friends here.

blackhole route

All traffic to destinations that match a blackhole route is silently discarded.

The general form is ip route add blackhole <ip>/<netmask>

example: ip route add blackhole 192.168.0.5/32, discards all traffic to host with IP address 192.168.0.5.