To measure network activity, use the netstat command. The netstat command can:
- Display active socket connections for each protocol
- Display routing table information
- Display a table of all network interfaces or a specified interface
- Display summary statistics for each protocol
For information and recommendations using the netstat command, consult your operating system manual.
Other commands that can be used in addition to netstat are: ss (utility to investigate sockets), ip (show / manipulate routing, devices, policy routing and tunnels).
To monitor various network statistics including TCP info, TCP/UDP package counts, ICMP and OSPF information, Ethernet load info, node statistics, IP checksum errors use iptraf command (only available if iptraf rpm package is installed).