The current port is used to view the system normally occupied what services used to start to solve the software because the port is occupied and lead to failure. You can view the server are currently logged in user to which the network. If you find IP addresses do not know, it may terminate its access.
example:
# View all system services ssh link netstat -ATP | grep sshd # only view the current system monitor network link, display port for the connection netstat -lnp
Options:
a: represents a view current system all the protocols, network link state
t: indicates tcp protocol packet chain
u: represents udp protocol packet chain
n: represents manner port View Chain
l: represents See only listening link
p: View network which links the PID of the program in use.
Keywords explained:
Proto: packet network protocol, is divided into TCP and UDP packets; Recv - Q: message buffer, sent from the remote process, information on the number of the current process has not yet been processed, unit: byte; the Send - Q: message buffer region, distal to the transmission process, the number of which has not been received message, unit: byte; the Local the address: the address and port number (the IP: port); Foreign the address: the network address of the remote process communication (IP: port) ( remote communication with the host); state: connected, there are established (eSTABLISED) and listening (lISTEN); PID / program name: command name PID number and a program of this service