net-tools

• net-tools is an old suite of network-related tools
  • netstat (for looking at open sockets, and the routing table)
  • ifconfig (interface config, for managing wired network interfaces)
  • iwconfig (same but for wireless interfaces)
  • route (for managing the routing table)
  • iptunnel (for creating tunnels)
  • arp (for managing the ARP cache) (Address Resolution Protocol)

iproute2

• iproute2 superceded net-tools, and includes more modern utilities
  • ss (for looking at sockets)
  • ip (for doing almost everything)
    • ip route (manage routing tables)
    • ip address (manage ip addresses)
    • ip neigh (manage ARP cache)
    • ip tunnel (manage tunnels)
  • iw (managing wireless interfaces)

The ip tool

• ip manages many many aspects of linux networking
• ip route = manage your routing table (try ip -c route)
• ip netns = manage network namespaces (try ip netns exec clab-www-pc1 ip -c route)
• ip address = manage ip addresses (don’t forget -c for colour - ip -c address)
• ip neigh = manage ARP cache. (Other hosts in the same layer 2 network are your neighbours.)
• ip -c neigh = with colour!

The ss tool

• ss gives us information about SOCKETS
• a socket is a channel for communicating with a process
• can be network sockets or unix sockets
• (we only care about network sockets right now)
• ss -t -l = listening TCP sockets
• ss -t -a = listening and non-listening TCP sockets
• ss -u -l = listening UDP sockets
• ss -t | grep ssh = show active ssh connections