Linux Network Tools - netstat


netstat is a command line tool that can list out all network (socket) connections on a system: TCP, UDP and Unix socket connections.routing tables, interface statistics, masquerade connections and multicast memberships.

List all connections

List TCP connections

List UDP connections

List listening connections

Disable reverse DNS lookup

netstat will try to find the hostname of each IP address by doing a reverse DNS lookup. This is slow.

List Process Name/ID

It is useful to know what process is using particular port.

Display Routing Table

Routing tables are used to compute the path of a packet. It is stores routes to network destinations and contains the topology of the network. Routing protocols and static routes help calculate the routing table.

Slightly more readable

Continuous output